BHT-212-MM
MODEL
MAINTENANCE MANUAL VOLUME 2
HANDLING AND SERVICING NOTICE The instructions set forth in this manual, as supplemented or modified by Alert Service Bulletins and other directions issued by Bell Helicopter Textron and Airworthiness Directives issued by the Federal Aviation Administration, shall be strictly followed.
COPYRIGHT NOTICE 1997 COPYRIGHT TEXTRONINC. BELL® HELICOPTER
Bell Helicopte A Subsidiaryof TextronInc. POST OFFICE BOX 482 * FORT WORTH,TEXAS 76101
ANDBELLHELICOPTER TEXTRON, A DIVISION OFTEXTRON CANADA LTD. ALLRIGHTS RESERVED
7
REVISION 5
-
JU
25 SEPTEMBER 1997
BHT-212-MM
PROPRIETARY RIGHTS NOTICE These data, excluding Chapter 4, Airworthiness
Limitations,
are
proprietary to Bell Helicopter Textron, Inc. Disclosure, reproduction, or use of these data for any purpose other than helicopter operation and/or maintenance is forbidden without prior written authorization from Bell Helicopter Textron, Inc.
Additional copies of this publication may be obtained by contacting: Commercial Publication Distribution Center Bell Helicopter Textron P. O. Box 482 Fort Worth, Texas 76101-0482
PN
BHT-212-MM
CHAPTER 6 CONTENTS Paragraph Number 6-1 6-2 6-3
DIMENSIONS AND CHARTS MAINTENANCE PROCEDURES
Title Airframe principal dimensions .................... Airframe reference lines .......................... Stations, waterlines, and buttock lines .........
Chapter/Section Number
Page Number
6-00-00 6-00-00 6-00-00
3 3 3
FIGURES Figure Number 6-1 6-2
Title Principal dim ensions ......................................................... Station diagram ..............................................................
Page Number 4 5
6-00-00
Page 1/2
BHT-212-MM
DIMENSIONS AND CHARTS 6-1.
AIRFRAME PRINCIPAL
3.
WATER LINES (W.L.):
Water lines are
DIMENSIONS.
horizontal planes perpendicular to, and measured along, the vertical axis of the
Figure 6-1 depicts the major dimensions of the helicopter. Due to variations in loading and landing gear deflection, all height dimensions are approximate. With ground handling wheels installed and fully extended, height will be increased by 5.0 in. (12.7 cm).
helicopter. Water line (0) is a plane below the lowest point on the fuselage. Water lines can be used to measure locations as described for station lines.
REFERENCE LINEmeasured 6-3.
STATIONS, WATERLINES, AND
BUTTOCK LINES.
4.
BUTTOCK LINES (B.L.):
Buttock lines
are vertical planes perpendicular to, and to, the left and right along the
ateral axis of the helicopter. Buttock line (0) is the plane at the vertical centerline of the helicopter. Buttock lines can be used to
measure locations as described for station lines.
1. GENERAL: Station lines, including buttock lines, water lines, tailboom and
5.
baggage compartment lines, elevator stations, and main and tail rotor blade stations are used to determine locations on, and within, the helicopter. All such locators lines are measured (in inches) from known points, Therefore, these lines will not be expressed in metric equivalents within this manual.
COMPARTMENT STATION LINES: Baggage compartment station lines are measured from the tailboom fuselage attach point to aft end of baggage compartment. Tailboom station lines are measured from aft end of baggage compartment to center of intermediate gearbox.
2. STATION LINES (F.S.): Stations are vertical planes perpendicular to, and measured along, the longitudinal axis of the
6. ELEVATOR STATION LINES: Elevator station lines (E.S.) are buttock lines extended through the elevator to elevator outboard tips.
TAILBOOM
AND
BAGGAGE
helicopter. Station (0) is a plane usually
Fuselage station lines (F.S.) and tailboom
forward of the nose of the helicopter. Several
stations (B.S.) also apply to the elevator.
stations are marked under the cargo door opening. Several station lines are shown on figure 6-2 at recognizable locations on the
7. VERTICAL FIN STATION LINES (V.F.S.): Vertical fin stations are parallel vertical lines
airframe. Other station locations can be measured from these lines. Tailboom
perpendicular to the center line of the tail rotor shaft, below the leading edge of the
stations, stations within the baggage compartment, and stations along the vertical fin are illustrated in the same manner. These
vertical fin. Fuselage stations also apply to the vertical fin.
stations are perpendicular to the centerline on
8.
the tailboom and fin, as applicable, because these components are mounted at an angle to the horizontal plane of the fuselage.
STATION LINES: Main and tail rotor blade station lines are measured from the center of hub to tip of blade.
MAIN AND TAIL
ROTOR
BLADE
6-00-00 Page 3
57 FT.0.68 IN. (PRIOR TO 30940) 57 FT. 1.68 IN. (30940 AND SUB.) 42 FT. 1.67 IN.
48 FT. NOTE
9 FT.4.48IN.
DIA
-4FT.
2 FT.6.58IN.
12FT.1.0IN.
Vertical dimensions will increase by approximately 1.5 inches when helicopter is empty.
28FT.11.12IN. 12 FT.9.05IN.
9 FT0.5IN.-
14 FT.
11o FLAPPING
(PRIOR TO
12 FT.
6.83 IN.
8F.7I
8 FT.6 IN.
(30940 AND
(PRIOR
30940) 8 3 IN. FT.
1.9 IN. 5 FT.
8 FT 8.4 IN.
GROUND LINE AT MID CG 11,200 LB GROSS WEIGHT
4 FT.
(30940
SUBQ)
EDGE
9 FT. 4.0 IN.
AT 11,200LB GROSSWEIGHT
212-M-6-1 212-900-15P
BHT-212-MM
140.34 116.40 128.32 74.25
92
166
37 BL 4
3 63
BL35
155.06
102
BL3486
178
BL34.23
211.06
3BL ROOFFRAME, 112.80123 129
BL 14 BEAM
BL15.25
BL14 BEAM
W 22
56.24 BL50
WL71.2
DOORBL 12
ENGINE
DOOR
192.85
218
BL 56.24
ROTOR
BL15.16 HELICOPTER
480.165
212-M-6-2-1
Figure 6-2.
Station diagram (sheet 1 of 2)
6-00-00 Page 5
BHT-212-MM
133.048
WL 136.515 -5o 133.506 TRANS
176.82
201.85
221.75 232.99
15246
63.3874.25 74.25
35
WL
98.25 TOP OF 98.25 PYLON
71.48
89.71 WL
6
214.17
TRACK
WL 38 43.40
54.89 ~WL
127.466
5344
FWDCANT
AFT CANT BLKMD.
BLKHD.
WL
WL102.265 WL102.265
TOPOF TAILBOOM TRACK
ATTACH BLK HD. WL 36
TRANS
WL22FLOOR
WL30.046
110.73 480.165 TAILROTOR
488.73
WL 138.378
WL122.05
23.60 244.61
300.81
SHAFT 341.48
420.5 363.54
75.30
17.42 WL 0 243.937
326.63
449.696
212-M-6-2-2
Figure 6-2.
6-00-00 Page 6
Station diagram (sheet 2)
BHT-212-MM
CHAPTER 7 CONTENTS Paragraph Number 7-1 7-2 7-3 7-4
MAINTENANCE PROCEDURES
Title Lifting helicopter ......................... Lifting complete helicopter (mast installed)..... Lifting complete helicopter (mast removed) .... Lifting complete helicopter (transmission
removed) ......... 7-5
LIFTING AND JACKING
........................
.
Lifting tailboom only ............................
Chapter/Section Number
Page Number
7-00-00 7-00-00 7-00-00
3 3 3
7-00-00
3
7-00-00
3
7-00-00
7
JACKING 7-6
Jacking helicopter ................................ FIGURES
Figure Number 7-1 7-2 7-3
Title Hoisting complete helicopter ................................................. Hoisting tailboom ............................................................ Jacking ......................................................................
Page Number 4 6 8
7-00-00 Page 1/2
BHT-212-MM
LIFTING AND JACKING 7-1.
4.
LIFTING HELICOPTER.
7-4. LIFTING COMPLETE HELICOPTER (TRANSMISSION REMOVED).
7-2. LIFTING COMPLETE HELICOPTER (MAST INSTALLED).
1. Attach a suitable hoist to pylon lift link (figure 7-1).
REQUIRED SPECIAL TOOLS REQUIRED NUMBER
204-011-178-001
Hoist slowly with a constant lifting force.
NOMENCLATURE
2.
Clevis
helicopter when hoisting. If lifting beyond reach from ground, use a rope to steady
Station a person at tail skid to steady
helicopter. 1. Attach a 204-011-178-001 hoisting clevis, or equivalent, to eye provided on retaining nut at top of main rotor mast. Connect suitable hoist and take up slack.
3. 7-5.
Hoist slowly with a constant lifting force. LIFTING TAILBOOM ONLY.
2. Station a person at tail skid to steady helicopter
when hoisting.
If lifting beyond
SPECIAL TOOLS REQUIRED
reach from ground, use a rope to steady helicopter. 3.
Hoist slowly with a constant lifting force.
7-3. LIFTING COMPLETE HELICOPTER (MAST REMOVED).
NUMBER
NOMENCLATURE
T101626
Sling assembly
1. Attach sling assembly, T101626, (3, figure 7-2) to suitable hoist and clevis.
SPECIAL TOOLS REQUIRED CAUTION NUMBER
NOMENCLATURE
204-040-929-101
Lift plate and cover
204-011-178-001
Clevis
DO NOT POSITION
STRAP
AREA OF BAGGAGE
IN
COM-
SUITABLE PARTMENT DOOR. STRAPS SHALL BE POSITIONED
AT BULKHEADS TO PREVENT 1.
Install
lift plate
(204-040-929-101
or
DAMAGE TO TAILBOOM SKIN.
equivalent) on transmission.
2. Position straps around tailboom at 2. Attach suitable hoist with clevis (204-011178-001 or equivalent) to lifting eye.
3. Station a person at tail skid to steady helicopter when hoisting. If lifting beyond reach from ground, helicopter.
use a rope to steady
bulkheads forward of vertical fin and aft of baggage door. Position sling at approximate center of gravity to maintain balance.
3. Support weight of tailboom with straps. Take up slack and disconnect tailboom from helicopter (Chapter 53). 7-00-00 Page 3
BHT-212-MM TAIL SKID (REF)
MAIN ROTOR TIE DOWN STRAP (REF)
ROPE (REF)
LIFT PROCEDURE
REMOVED
DETAIL
Figure 7-1.
7-00-00 Page 4
A
Hoisting complete helicopter
4.
Pylon lift link
212-M-7-1 204-011-178A
BHT-212-MM NOTE
CAUTION
For use of support
assembly,
T102012, refer to Chapter 53. ENSURE TAILBOOM ROTATE IN STRAPS 4.
DOES NOT
Hoist tailboom slowly with a steady force.
7-00-00 Page 5
BHT-212-MM
3
BAGGAGECOMPARTMENT DOOR RIGHT SIDE
1.
Hoist (1 Ton min. capacity)
2. 3. 4.
Clevis Sling assembly T101626 Strap NOTE
Position sling assembly on tailboom to maintain balance. CAUTION
A
ENSURE STRAPS (4) ARE POSITIONED AND DOUBLE WRAPPED AT BULKHEADS TO HELP PREVENT TAILBOOM FROM FLIPPING OVER. DO
NOT POSITION
STRAPS (4) IN AREA OF
BAGGAGE COMPARTMENT DOOR. 212-M-7-2
Figure 7-2. Hoisting tailboom
7-00-00 Page 6
BHT-212-MM
JACKING
7-6. JACKING HELICOPTER.
AREA IF WIND VELOCITY EXCEEDS 20 KNOTS. HEAD HELICOPTER WIND WIND.
SPECIAL TOOLS REQUIRED
NUMBER
INTO PREVAILING
PROVIDE SUITABLE SURFACE
NOMENCLATURE
FOR JACKS TO REST ON (LEVEL
Regent No. 988S, or Hydraulic tripod jacks equivalent (4 each, 6000 lb.
HARD SURFACE VALENT).
OR EQUI-
capacity) 1.
Raise helicopter as follows:
10).
WARNING DO NOT ALLOW PERSONNEL TO
b. Place four hydraulic jacks in position under jack point fittings (figure 7-3).
CRAWL INTO OR ONTO HELICOPTER
WHILE
WHILE
HELICOPTER
RAISING
OR
IS
c.
Operate jack handles slowly and evenly
at all four positions, being careful to keep
SUPPORTED ON JACKS. ROPE OFF AREA AND DISPLAY SIGNS
helicopter height.
JACKS".
2.
STATING 'HELICOPTER ON
CAUTION
level, as it is raised to desired
Lower helicopters as follows:
a. Slowly and carefully lower all four jacks simultaneously.
b. Remove jacks and other equipment DO NOT PLACE HELICOPTER ON
JACKS
from area.
IN AN UNSHELTERED
7-00-00 Page 7
BHT-212-MM
BLADE TIEDOWN (REF)
7-00-00 Page 8
SUITABLE BLOCKS R SUPPORT
1. Forward Jack Fitting (2) 2. Aft Jack Fitting (2)
212-M-7-3 212-900-001
Figure 7-3.
7-00-00 Page 8
Jacking
BHT-212-MM
CHAPTER 8 CONTENTS Paragraph Number 8-1 8-2 8-3 8-4 8-5 8-6 8-7 8-8 8-9
WEIGHT AND BALANCE
MAINTENANCE PROCEDURES
Title Weight and balance .............................. Leveling ........................................ Weighing ....................................... Determining center of gravity location .......... Determining amount of ballast required ........ Weight empty center of gravity charts - kits.... Nose ballast installation and removal ............. Tail skid ballast ................................... Weight and balance sample problem .............
Chapter/Section Number
Page Number
8-00-00 8-00-00 8-00-00 8-00-00 8-00-00 8-00-00 8-00-00 8-00-00 8-00-00
3 3 3 5 5 7 8 8 22
FIGURES Figure Number 8-1 8-2 8-3 8-4 8-5 8-6 8-7 8-8 8-9 8-10 8-11 8-12 8-13 8-14 8-15 8-16
Title Leveling ...................................................................... Weight and balance.......................................................... Weight empty center of gravity .............................................. Weight empty center of gravity with emergency flotation, 212-706-021 ...... Weight empty center of gravity with emergency flotation, 212-706-021, and auxiliary fuel tanks, 205-706-044 ........................................... Weight empty center of gravity with emergency flotation, 212-706-021, and auxiliary fuel tanks, 205-706-045 ............................................ Weight empty center of gravity with emergency flotation and auxiliary fuel tanks, 212-899-243 (one 90 and one 20 gallon tank installed)............... Weight empty center of gravity with emergency flotation, 212-706-021, and auxiliary fuel tank, 212-899-243 (one 90 gallon tank installed) .............. Weight empty center of gravity with auxiliary fuel tanks, 205-706-044....... Weight empty center of gravity with auxiliary fuel tanks, 205-706-045....... Weight empty center of gravity with auxiliary fuel tanks, 212-899-243 (one 90 and one 20 gallon tank) .................................................. Weight empty center of gravity with auxiliary fuel, 212-899-243 (one 90 gallon tank installed) ........................................................ Weight empty center of gravity with floats, 205-706-050 ..................... Nose ballast ................................................................. Tail skid ballast .............................................................. . .......................................... Actual weight record sample
Page Number 4 6 9 10 11 12 13 14 15 16 17 18 19 20 21 23
8-00-00 Page 1/2
BHT-212-MM
WEIGHT AND BALANCE 8-1.
WEIGHT AND BALANCE.
3.
Adjust height of jacks to bring plumb bob
exactly over the point where two lines The center of gravity (CG) is considered to be the balancing point of a body for weight and
intersect at 0° on leveling plate. Helicopter is now leveled both longitudinally and laterally.
balance purposes. The helicopter can be compared to a pendulum; the point of
4. Remove plumb bob.
suspension being where the main rotor hub intersects the mast (the pendulum weight being the helicopter). If the pendulum weight is allowed to stop, it will come to rest directly
8-3.
below the suspension point. For example: If
configuration
the CG of a helicopter is aft of the hub-mast intersection, the helicopter will be tail low in flight. The pilot can correct this condition by moving the cyclic control stick forward. If the
WEIGHING.
The helicopter
should
be weighed
in a
as near Weight Empty as
possible NOTE
required movement of the stick is great enough, the pilot will use all available control,
Weight Empty condition is the basic
thus limiting maneuverability and forward
helicopter
speed. Since such loss of maneuverability is unsafe, care shall always be taken to keep
ballast, special equipment, transmission oil, hydraulic fluid,
the helicopter
unusable fuel, and undrainable oil.
operational
center
limits.
of gravity
within
Moving the CG is
accomplished by adding or removing ballast.
together
with seats,
RefertoFAR29.
1. All kits, transmission oil, and hydraulic fluid may remain aboard.
NOTE
For additional weight and balance information, operators in territorial United States shall refer to FAR 29. Operators outside territorial United
States shall refer to information issued by the licensing authority, 8-2.
Ensure baggage compartment is empty.
3. Scale accuracy shall be within plus or minus 1.0 lbs.
4. Position scales in an approximately level area, and check for proper adjustment to zero position.
LEVELING. NOTE NOTE
1.
2.
| CAUTION
Leveling plate (2, figure 8-1) is graduated in increments of 1/4 ° .
WEIGHING
SHOULD
The plate is located on cabin floor
ATTEMPTED
IN AN OPEN AREA
just inside left passenger cargo
BECAUSE
door. A slotted hole in upper door frame is provided for suspension of a plumb bob (1).
EFFECTS OF WIND.
Support helicopter on jacks (Chapter 7).
NOT BE
OF THE ADVERSE
5. Position a scale and jack assembly under each jack pad or under each forward jack pad and one aft jack pad. Raise helicopter clear of floor.
2. Hang plumb bob (1) in slotted opening in door frame with point of plumb bob just above leveling plate (2) on cabin floor. 8-00-00 Page 3
BHT-212-MM
1. 2.
.
Plumb Bob Leveling Plate
Figure 8-1.
8-00-00 Page 4
Leveling
BHT-212-MM
NOTE For electronic scales, ensure load cells and adapters are fastened securely to jacks. Accomplish scale manufacturers recommended warm up time and zero each load cell.
1. This distance from F.S. 0.0 to a line through centers of forward jack pads is called the forward arm. The distance from F.S. 0.0 to a line through the center of aft jack pads is called the aft arm. The forward arm is 61.69 in. (15.64 cm) and the aft arm is 211.58 in. (53.74 cm) (figure 8-2).
6.
Level helicopter (paragraph 8-2).
2. Multiply total net weight of forward scales by forward arm. The product is called forward moment and is expressed in inch pounds
7.
Balance each scale and record its
(in.lbs.).
reading. 3.
Multiply total net weight of aft scales by
8. Lower helicopter to surface. Weigh jacks, blocks, and any other equipment used between scales and helicopter. Deduct this weight (tare) from actual (first) scale readings to obtain net scale weights.
aft arm. This is aft moment in in.lbs. 4 Add forward and aft moments and divide by total "As Weighed" weight. The quotient is helicopter "As Weighed" CG in inches aft of F.S. 0.0.
NOTE
NOTE
For
electronic
scales,
The above procedure may be stated
lower
helicopter and verify each cell returns to zero setting. Variations from zero are considered tare and shall be added or subtracted from readings.
in equation form as follows: As Weighed CG = (Net Wt. Fwd Scales) (61.69) + (Net Wt. Aft Scales) (211.58) = Total Net (As Weighed) Weight
9. Total "As Weighed" weight is the sum of the individual net scale weights. 8-4. DETERMINING CENTER OF GRAVITY LOCATION.
(TABLE I.D.910404)
8-5. DETERMINING AMOUNT OF BALLAST REQUIRED.
1. Weight Empty center of gravity chart (figure 8-3) is to be used for all configurations except when following kits are installed.
.CAUb CAUTIONi
a. Auxiliary Fuel, 205-706-044, THE WEIGHT EMPTY CENTER OF
GRAVITY
CHARTS
b.
Auxiliary Fuel, 205-706-045,
PRESENTED
AS A GUIDE
c.
Auxiliary Fuel, 212-899-243,
d.
Emergency Flotation, 212-706-021,
ARE TO
PROPERLY BALLAST THE IF HELICOPTER HELICOPTER. CANNOT BE BALANCED WITHIN
THESE
RESTRICTIONS,
THE
e. Floats, 205-706-050.
GROSS WEIGHT VERSUS CENTER OF GRAVITY LIMITS PRESENTED
IN THE APPROPRIATE FLIGHT
MANUAL
SHALL
NOT BE
EXCEEDED. GENUINE
BELL PARTS ARE YOUR BEST VALUE
8-00-00
Rev. 3
Page 5
BHT-212-MM 530
479.4 50
0
150
100
REF DATUM FUS STA 0.0
200
250
350
300
FUSSTA 133.5
200
450
400
500
550
7 IN1337
150
WL 136.5 INTERSECTION WL 137.5 -HUB AND MAST PASS.DOOR
100
DRIVE SHAFT
CREW DOOR
18 IN.
50
MAST SERVICE
DECK i
JACK PADS- AFT FUS STA 211.58 CABIN FLOOR
W.L 0 HINGED DOOR POST
-20 ININ. -20 A
JACK PADS - FWD FUS STA 61.69 B
212-M-8-2
Figure 8-2.
Weight and balance
flights, as applicable) then only add sufficient tail ballast, not to exceed 50 lbs. (22.68 kg), to move CG to applicable forward CG limit, if derived weight CG is aft of aft limit, add only sufficient nose ballast, not to exceed limits
NOTE For center of gravity charts applicable when above listed kits are installed, refer to paragraph 8-6. 2. Figure 8-3 has a forward CG limit for VFR flights, a forward CG limit for IFR flights and an aft CG limit. The CG limits are for the
following flight configurations.
specified in figure 8-14, to move CG to aft limit
4.
When Weight
Empty CG is not within
acceptable range shown in figure 8-3, use
a. Line A is forward CG limit for basic or IFR configuration helicopters for VFR flights if adding tail ballast.
following formula to determine amount of ballast required.
approximate = ?
Ballast - arm required ARM
b. Line B is forward CG limit for IFR configuration helicopters adding tail ballast.
on IFR flights
if
c. Line C is aft CG limit for basic or IFR helicopters for IFR or VFR configuration
flights, if adding nose ballast.
3. Actual Weight Empty CG can fall anywhere between aft and forward CG limit (VFR or IFR, whichever is applicable) and be acceptable; however, if derived Weight Empty CG is forward of forward limit (VFR or IFR 8-00-00 Page 6
NOTE
Derived weight and CG are "as weighed" values plus those Weight Empty items which may have been
omitted, and minusthosetems
which are not part of Weight Empty.
is apprd
and of derived weit eigt eie n nter lne on ure 8-3 nearest CG
BHT-212-MM
5. Check derived weight plus ballast and
Actual Weight Empty CG can fall
resultant CG on figure 8-3; add or remove ballast if necessary to arrive at desired CG.
anywhere between aft and forward limit. The dashed section of forward
limit allows a 0.10 in. (2.54 mm) tolerance range for actual CG.
NOTE
For weight and balance sample
flotation,
212-706-021
b. Emergency flotation, 212-706-021, with 205-706-044 auxiliary fuel tanks (figure 8-5).
8-6. WEIGHT EMPTY CENTER OF GRAVITY CHARTS - KITS. 1.
a. Emergency (figure 8-4).
problem, refer to paragraph 8-9.
When any of following kits are installed,
c. Emergency flotation, 212-706-021, with 205-706-045 auxiliary fuel tanks (figure 8-6).
the applicable referenced center of gravity chart shall be used. NOTE
d. Emergency flotation, 212-706-021, with 212-899-243 auxiliary fuel (one 90 gallon and one 20 gallon tank installed) (figure 8-7).
Weight Empty Center of Gravity Charts are guidelines provided by Bell Helicopter Textron to simplify
e. Emergency flotation, 212-706-021, with 212-899-243 auxiliary fuel (one 90 gallon tank installed) (figure 8-8).
ballast computations for the operators.
The limits are derived
f.
Auxiliary fuel tanks, 205-706-044,
using Gross Weight Center of
except when 212-706-021 emergency
Envelope and extreme Gravity. oad i n g forward a n d aft configurations include combinations
flotation or 205-706-050 floats are installed (figure 8-9). The CG limits on figure 8-9 are as follows:
of standard crew and passenger weights and various fuel loadings from the tables. Seating restrictions
and crew weight
(1) Line A is forward CG limit for VFR flights if adding tail ballast.
ranges are
accounted for in the derivations, but loading is baggage compartment not. Whenever a helicopter has a unique
situation such as: Nonstandard seating arrangement, nonstandard
(2) Line B is forward CG limit for IFR flights if adding tail ballast. (3) Line C is aft CG limit for IFR or VFR flights if adding nose ballast.
g. Auxiliary
fuel tanks, 205-706-045,
crew and/or passenger weights, baggage compartment being loaded, or weight empty exceeds chart, the forward and aft extremes for that
except when emergency flotation, 212-706021, or floats, 205-706-050, are installed, figure 8-10. If helicopter is used for IFR flights, Weight Empty should be ballasted to
configuration should be computed
fall within 0.10 in. (2.54 mm) of aft limit,
and checked against Gross Weight
provided ballast limits are not exceeded.
Center of Gravity
helicopter is used for VFR flights, Weight
Envelope to
compute ballast requirements.
The
If
Empty can fall anywhere between aft and
Gross Weight Center of Gravity Envelope is the final authority for
forward limit.
determining ballast requirements. Refer to weight and balance chapter in appropriate BHT-212-FM manual for additional information.
h. Auxiliary fuel tanks, 212-899-243 (one 90 and one 20 gallon tank installed), except when emergency flotation, 212-706-021, or floats, 205-706-050, are installed, figure 8-11. The CG limits on figure 8-11 are as follows: 8-00-00 Page 7
BHT-212-MM
(1) Line A is forward CG limit for VFR flights if adding tail ballast.
TAIL SKID BALLAST.
8-8.
1. Installation (2) Line B is forward CG limit for IFR flights if adding tail ballast. (3) Line C is aft CG limit for IFR or VFR flights if adding nose ballast.
of equipment at forward
stations and nose of helicopter may require addition of ballast (2 and 3, figure 8-15) and/ or inside tail skid (5) to aft section of tailboom (6). 2.
After installation of equipment, a weight
i. Auxiliary fuel, 212-899-243 (one 90 gallon fuel tank installed), except when
and balance check shall be accomplished. Ballast required to correctly locate center of
emergency flotation, 212-706-021, or floats, 205-706-050, are installed, figure 8-12. The CG limits on figure 8-12 are as follows:
gravity should be installed on or in tail skid (5).
(1) Line A is forward CG limit for VFR flights in adding tail ballast.
3. Ballast may be added to a maximum of 50 lbs. (22.68 kg) on and in tail skid. Ballast weights should be installed in a combination
to provide amount required by weight and (2) Line B is forward CG limit for IFR flights if adding tail ballast.
balance check. NOTE Ballast weights (2 and 3) shall be
(3) Line C is aft CG limit for IFR or VFR flights if adding nose ballast.
installed in combination with
j. Floats, 205-706-050 (figure 8-13). The Weight Empty CG may fall anywhere between forward and aft limit. 2.
Use applicable
Service Instructions
for
ballast installation instructions.
washers (1) and clamps (4) on tail skid (figure 8-15).
Ballast, when required, should be
4.
installed on that portion of tail skid located
inside tailboom (figure 8-15) or inside tail skid.
8-7. NOSE BALLAST INSTALLATION AND REMOVAL.
NOTE
1. Determine amount of ballast to be added or removed and moment arm. Refer to figure
When ballast is installed inside tail skid, tail skid shall be filled
8-14 for nose ballast station and butt line
completely full, approximately 15
(B.L.) moment arms. Add or remove nose ballast weight as symmetrically as possible.
lbs. (6.8 kg).
2. If ballast weight must be added, refer to figure 8-14 to determine allowable number of ballast plates in each location. Inspect nose compartment to determine where additional ballast plates may be added. 3. If ballast weight must be removed, inspect nose compartment to determine locations where ballast weight plates may be removed.
Install ballast inside tail skid as follows:
5.
a. Remove weight weight. b. Remove phenolic end of tail skid.
and record tail skid plug from forward
c.
Completely fill tail skid with lead shot.
d.
Install phenolic plug in forward end of
tail skid and reweight tail skid. Determine amount of ballast added (subtract tail skid empty weight from filled tail skid weight). Stencil forward end of tail skid, and inboard 8-00-00 Page 8
BHT-212-MM
170 LB. PILOT SEENOTE 7400
FUSELAGE STATION
-
INCHES
NOTES 2. 1.
Use this chart when 212-706-032 or 212-706-042 float kit is installed. 21 2-M-8-3 Weight ofthegravity This chart to Figure be used 8-3.. for all configurations when following areitiiinstalled. i~i FORWA iili'iliiiRDempty LIMIT ~except ~center iiiiliiis. ililiiiil
~": ;...... ............ .' .... ::i::! . ................ ::
1. 2.
Auxiliary fuel 205-706-044 Auxiliary fuel 205-706-045
3. 4. 5.
Auxiliaryfuel 212-899-243 Emergencyflotation 212-706-021 Floats 205-706-050 ila32ysi
0 Page 9
Page 9
BHT-212-MM
W EIGHT EMTPY 170 POUND PILOT JP-5 FUE L
NOTE: THIS CHART TO BE USED WHEN 212-706-021 EMERGENCY FLOTATION IS INSTALLED:
7600 -
AFT LIMIT 7300 7200-
700
6800
6006600
Page 10
00
Page 1 0
FORWARD LIMIT
--
BHT-212-MM
MODEL 212 WEIGHT EMTPY 170 POUND PILOT JP-5 FUEL EMERGENCY FLOTATION 2205-706-044 AUXILIARY FUEL
i
7500
8-00-00 Page 11
BHT-212-MM
6300
FUSELAGE STATION -INCHES
Figure 8-6.
8-00-00 Page 12 Page
21 2-M-8-6
Weight empty center of gravity with emergency flotation, 212-706-021, and auxiliary fuel tanks, 205-706-045
BHT-212-MM
WEIGHT EMPTY JP-5 FUEL NOTE 212-899-243 AUXILIARY FUEL (ONE 90 GALLON AND ONE 20 GALLON TANK INSTALLED).
7600 7500
FORWARD LIMIT 7200 7100
6900
-
680070 6600600-
6100-
140.5
141.0
141.5
142.0
142.5
FUSELAGE STATION - INCHES 212-M-8-7
Figure 8-7.
Weight empty center of gravity with emergency flotation and auxiliary fuel tanks, 212-899-243 (one 90 and one 20 gallon tank installed) 8-00-00
Page 13
BHT-212-MM
WEIGHT EMPTY 170 LB. PILOT JP-5 FUEL 212-706-021 EMERGENCY FLOTATION 212-899-243 AUXILIARY FUEL
AND 212-899-243 AUXILIARY
FUEL (ONE 90 GALLON TANK INSTALLED)
7600
7300--
FORWARD LIMIT
AFT
6900
6700
-
8-00-00 6500 6400 -
6200
Figure 8-8.
8-00-00
Weight empty center of gravity with emergency flotation, 212-706-021, and
BHT-212-MM
.
WEIGHT EMPTY 170 LB.PILOT
AUXILIARY SEENOTE FUEL, 205-706-044
7600
VFRAFT
7400
6
FSGI-
--
-C ------
65006400
6100 6000
8-00-00
BHT-212-MM
AUXILIARY FUEL, 205-706-045 WEIGHTEMPTY LB.PILOT 170 JP-5 FUSELAGE FUEL STATION - INCHES
·
7000
6600
----
BHT-212-MM
7600
VFR FORWARD LIMIT
6500 -n
'
o
90 and one 20 gallon tank)
Page 17
8-00-00
BHT-21 2-MM
WEIGHT EMPTY 170 LB. PILOT JP-5 FUEL
SEENOTE NOTE
Do not use this chart when emergency flotation, 212-706-021 or floats, 205-706-050 are installed.
7600 7500 VFR FORWARD LIMIT
7400
INI -IFRAND
7300
AFT LIMIT
100
700
6800
IFR FORWARD LIMIT
6700
6600-6500
6400 6300 6200
6100 6000 140.5
141.0
141.5
142.0 142.5 143.0 FUSELAGE STATION - INCHES
143.5
144.0 212-M-8-12
Figure 8-12. Weight empty center of gravity with auxiliary fuel, 212-899-243 (one 90 gallon tank installed) 8-00-00 Page 18
BHT-212-MM
WEIGHTEMPTY 170 POUNDPILOT
_
FLOATS, 205-706-050
NOTE No IFR flights allowed with floats, 205-706-050
installed.
700 7400--7300
FORWARD LIMIT
7200 AFT LIMIT
6900:
66006800
6700 6000 6500 6400 6300 62 6200-
140.5
141.0
141.5
142.0
142.5
143.0
143.5
FUSELAGE STATION -INCHES
212-M-8-13
Figure 8-13.
Weight empty center of gravity with floats, 205-706-050
8-00-00 Page 19
BHT-212-MM
21
2457 212-030-245-9
0. TO 1.1 LBS (0.408 TO 0.410 kg) R AND L MAX QTY. PERSIDE 3 UNIT WT. (LBS) 1.0 (0.454 kg) STA. -1.8 BL± 20.1
2.4TO 2.6 LBS (1.089 TO 1.179 kg) R AND L MAX QTY. PERSIDE 3 UNIT WT. (LBS) 2.5 (1.133 kg) STA. -4.5 BL± 18.2
030-030-245-11
212-030-245-13
212-030-245-15
3.9 TO 4.1 LBS (1.769 TO 1.860kg) R AND L MAX QTY. PERSIDE 4 UNIT WT. (LBS) 4.0 (1.814 kg) STA. - 4.1 BL± 28.8
7.9 TO 8.1 LBS (3.583 TO 3.674 kg) R AND L MAX QTY. PERSIDE 2 UNIT WT. (LBS) 8.0 (3.628 kg) STA. - 4.1 BL± 20.8
18.9 TO 19.1 LBS (8.573 TO 8.663 kg) R AND L MAX QTY. PERSIDE 2 UNIT WT. (LBS) 19.0 (8.618 kg) STA. - 4.7 BL± 20.5
-7 TYPICAL R AND L 212-030-173 MAX QTY. 1 STA. - -5.7 BL +7.9
-9 TYPICAL R AND L -11 TYPICAL RAND L -13 TYPICAL RAND L
-15 TYPICAL R AND L
ACTUAL WEIGHT IS STAMPEDON EACH WEIGHT, 212-030-173
NOTE Plus (+) indicates right lateral moment and minus (-) indicates left lateral moment for buttock line (BL) locations.
Figure 8-14.
8-00-00 Page 20
Nose ballast
212-M-8-14
BHT-212-MM
4
.
1. Washer (4) 204-071-566-5 (2) 204-071-566-3 2. 3. Ballast 204-071-566-1 Ballast (3)
Nominal weight each 6.3 pounds (2.86 kg)
4.
Clamp (6) 204-040-811-1
5. 6.
Tail skid Tailboom
7. 8.
Center of ballast location, approximately F.S. 441.0 Center of gravity for lead shot, approximately F.S. 457.0 212-M-8-15
Figure 8-15. Tail skid ballast
8-00-00 Page 21
BHT-212-MM
side of each tail skid access panel with actual
ballast
Desired
CG
weight of ballast added.
Range for new weight (5954+100).
A
reasonable ballast arm is -5. Thus: B
5954.2 (144.35-147.05) -5-144.35
Install tail skid.
e.
and use a CG within
f. Add additional ballast, as required, not to exceed 50 pounds (22.68 kg) total ballast.
8-9. WEIGHT AND BALANCE SAMPLE PROBLEM.
5954.2(-2.7) -149.358
lbs
Figure 8-14 presents ballast weights and locations. The ballast selected should be placed as symmetrically as possible and
The sample Actual Weight Record (figure 8-
amount used shall not be less than amount necessary to ensure satisfactory CG location.
16) can be used as a guide to follow a from weighing to weight and helicopter balance check with intermediate steps to
In this case four 212-030-245-15 plates of 19 lbs. (8.62 kg) each and four 212-030-245-13 plates of 8 lbs. (3.63kg) each equals the 108
change Weight Empty configuration.
pounds (48.98kg)
derived above.
moment for this ballast is -488 in.lbs.
The "As Weighed" condition (paragraph 8-3)
The The
Derived Weight and Moment plus Ballast
is shown in the block at top of Actual Weight Record. "Net" weight is 'Scale' weight less
Weight and Moment is Weight Empty Weight Moment. The Weight Empty Moment divided by Weight Empty Weight is Weight
tare.
Empty CG.
Center of gravity determination (paragraph 84) is shown directly below the 'As Weighed'
helicopter weighs 6062.2 with a 144.35 CG. a 8-3 indicates on figure A recheck satisfactory operating condition
block.
Further calculations on the Actual Weight
This helicopter is assumed to be dry so all
Record will confirm operation is within flight limits.
Weight Empty fluids shall be added in determining Derived Weight. These fluids include hydraulic fluid and all transmission and gearbox oils together with unusable fuel and undrainable engine oil.
was originally
This helicopter
This addition indicates the
Sample flight calculations demonstrating fuel burn, off-loading passengers, etc., are presented in Model BHT-212-FM. A different Weight Empty and CG was used but the principle is the same.
weighed without seats.
Therefore, seat weight shall be added. These items added to 'As Weighed' comprise
will of the helicopter The configuration probably change several times due to addition
"Derived Weight" and CG to be used in determining ballast required. The "Derived
of kits, engine change, etc. following examples:
Weight" is 5954.2 lbs. (2700.8 kg) and the
CG is F.S. 147.05. Using the formula in paragraph 8-5, step 4: 5954.2 (Required CG - 147.05)
= Ballast
Ballast Arm - Required CG Required CG is located by using figure 8-3.
Assume approximately 100 lbs. (45.36 kg) 8-00-00 Page 22
refer to the
BHT-212-MM BELL HELICOPTERTEXTRON ACTUAL WEIGHT RECORD
MODEL 212 DATEWEIGHED 8- 13 -74SCALE READINGS (LBS )
SKID
CONFIGURATION
FORWARD JACKPOINTF.S.
61.69
B L. - 30 0
FORWARD JACKPOINT, F.S
61 69
BL
AFTJACKPOINTFS
30XXX
SERIAL NUMBER
211 58
300 1453
B.L.
TOTAL
SCALE
4
TARE
NET
5
85
99
3296
394-
5668
9
3495 QZ
N LATERAL CALCULATIONS IS RIGHT
LONGITUDINAL C.G. AS WEIGHED
C.G
2372
6169
( 3296
21158
)
96
IN
TOTAL WEIGHT LATERAL C.G.. AS WEIGHED
CG - -300(
385
) 300(
197
)-1453 1 329
WEIGHT EMPTY DERIVATION
WEIGHT
5
ASWEIGHED
ADD:Unusable
FuE I
Xmsn
Oil
BALLAST WEIGHT EMPTY.SKID
-68
=
+116
)
TOTAL WEIGHT
566
LONGITUDINAL ARM MOMENT
148.8s 84 53,
03
LATERAL ARM MOMENT
+003
+ I6
+2-2.3
142.8 + 404
0
0
+ 273
17.9 +4-721
0
0
-4.
o
+108.0 CONFIG
144.3
- 48 87271
IN
02
+/39
MOST FORWARD C.G
+ PILOTAND COPILOT
*
3400
+ PASSENGERS (4) CENTER SEAT FACING AFT PASSENGERS (5), BACK SEAT FACING FWD.
470
15980
0
0
*
6800
870
59160
0
O
+
8500
1170
+
99450
0
0
+ OIL, ENGINE + FUEL,MOST FORWARD
+ 245 + 472.0
169.1 1276
* +
4146 60227
0 0
0 0
MOST AFT C G
Page 1 of 2
Figure 8-16.
212-M-8-16
Actual weight record sample
8-00-00 Page 23
BHT-212-MM
Changes made as a result of configuration changes shall be documented and a current Weight Empty and CG shall be available at all
times.
The following is the basic helicopter with dual controls, copilot instruments, and emergency floatation added:
The following demonstrates steps
necessary when changes are made. Weight
Longitudinal Lateral 875271
+ 0.02
+139
36.10
+
801
-22.50
-500
+ 20.1
10.80
+
218
-15.10
-304
+579.0
89.00
+51531
+ 0.90
+521
6684.3
138.80
927821
-0.02
-144
Previous weight Empty
6063.0
144.36
Add: Dual controls
+ 22.2
Copilot instruments Emergency flotation Derived Weight
A check on figure 8-3 shows the CG to be too far forward indicating a need for removal of nose ballast. The ballast computation formula may be used or trial and error is acceptable. Weight Empty
In this case, removal of previously added 108 lbs. (48,98 kg) is acceptable.
-108.0 6576.3
A recheck on figure 8-3 verifies this CG at indicated weight to be acceptable.
+488 141.16
928309
-0.02
-144
BHT-212-FM and will not be approached unless extreme lateral payload position is encountered.
The above sample data has not covered lateral CG. The method of calculating lateral CG is shown on the Actual Weight Record. Maximum asymmetric limits are shown in
8-00-00 Page 24
If it is necessary to load in this manner, a lateral check should be made.
BHT-212-MM
CHAPTER 9 CONTENTS -
TOWING
MAINTENANCE PROCEDURES
Paragraph
Number 9-1 9-2
Chapter/Section
Page
Number
Number
9-00-00 9-00-00
3 3
Title General ................................... Operation ......... ............................ FIGURES
Figure Number
Title
Page Number
9-1
Towing helicopter............................................................
5
9-2
Crosstube strap installation
6
.................................................
9-00-00 Page 1/2
BHT-212-MM
TOWING 9-1. GENERAL.
WEIGHTS
AS
SHOWN
IN
PARAGRAPH 1. BELOW.
1. The helicopter towing
by attaching
may be equipped for two ground handling
1. Install strap on aft cross tube of landing
wheel assemblies (3, figure 9-1) to landing
gear part number and gross weight as
gear skid tubes.
follows: WARNING
Part Number
Type
Gross Weight
205-050-400-27
Standard
205-050-400-71
Standard
Above 8000 pounds Above 9000
RED
205-050-400-
High Skid
Above 9000
STREAMER WARNING FLAG
101pounds
DO NOT START ENGINES WITH
AFT CROSS TUBE STRAP (4, AFT CROSS FIGURE 9-2)) INSTALLED. INSTALLED.
RED
pounds pounds
REMOVE CROSS TUBE STRAP SHALL BE INSTALLED ON PILOT CYCLIC STICK ANY TIME STRAP IS INSTALLED ON SKID GEAR.
2. Helicopters with aft strap modification (T.B. 212-82-58A) incorporated may exceed 8000 pounds gross weight for towing when a
DO NOT USE GROUND HANDLING GEAR, 212-050-200, WHEN
cable strap with turnbuckle between skid tubes.
HELICOPTER GROSS WEIGHT IS IN EXCESS OF 9500 LBS.
9-2.
is installed
DAMAGE TO GROUND HANDLING GEAR MAY RESULT.
OPERATION.
2. Tie down main rotor blades (Chapter 10). CAUTION
3.
Install ground handling wheels as follows:
WHEN GROUND HANDLING OR
CAUTION
TOWING HELICOPTER WITH STRAPPED CROSS TUBES, TAKE
CARE TO PREVENT DAMAGE.
THE
PASS OVER HANGER RAILS, GROUND HOLES OR SIMILAR OBSTRUCTION SLOWLY TO LESSEN IMPACT FORCES ON
INSTALLATION APPROVED BY HELICOPTER MANUFACTURER (BHT) IS WITH FIXED PINS DIRECTED IF IF FORWARD. DIRECTED FORWARD.
ONLY
METHOD
OF
REQUIRED, HELICOPTER MAY BE FORWARD OR IN BALLASTED
BAGGAGE COMPARTMENT TO
CAUTION STRAPPING CROSS TUBES IS
ACHIEVE
A NEUTRAL C.G.
RELATIVE
TO GROUND
HANDLING WHEELS.
REQUIRED IF GROUND HANDLING OR TOWING HELICOPTER ABOVE 9-00-00 Page 3
BHT-212-MM
a. Position ground handling wheels over skid tube and align attaching fixed pins with eyebolts on tube. b.
Station a person at tail skid to keep
helicopter level during ground handling or towing.
d.
Disconnect ground wire from helicopter.
e.
Tow or handle helicopter slowly.
Move
helicopter on wheels using tail skid to maintain balance.
Remove ground handling wheels as
4.
follows:
a. Lower skid tubes to the ground by retracting the ground handling wheels on each skid tube at same time.
DO NOT LEAVE HELICOPTER WITH GROUND UNATTENDED IN WH EELS HAN DLI NG EXTENDED POSITION.
c. Extend wheels on both skid tubes at same time to raise skid tubes for ground clearance.
9-00-00 Page 4
b. Remove fixed pins from eyebolts and remove wheels from skid tubes. c.
Connect ground wire to helicopter.
BHT-212-MM
SEECAUTION
helicopter Towing wheel assembly 204-050-200 3. Ground handling 4.
212-M-9-1
Ground handling wheel assembly 212-050-200 gross weight - heavy gross
USE ONLY ONLY 212-050-200
GROUND HANDLING GROUND HANDLING THEN POUNDS.WEIGHTS WHEEL8,000 FOR FOR TOWING WEIGHTS GREATER GREATER
THEN 8,000 POUNDS. 212-M-9-1
Figure 9-1. Towing helicopter
9-00-00 Page 5
BHT-212-MM
CONTROLSTICK
1. ATT
RE 3.
4. 5.
Tow bar
Ground handling wheel assembly 212-050-200 only Crosstube strap TB212-82-58A Turnbuckle
CAUTION
DO NOT ATTEMPT TO REDUCE NATURAL GEAR SPREAD WHILE LOADED. SNUG UP TURNBUCKLE (5) WITH WEIGHT ON SKID TUBES.
Figure 9-2. Crosstube strap installation
9-00-00 Page 6
212-M-9-2
BHT-212-MM
CHAPTER 10 CONTENTS Paragraph Number 10-1 10-2
10-3 10-4 10-5
PARKING AND MOORING
MAINTENANCE PROCEDURES
Title Parking and mooring ............................. Normal conditions ..............................
Turbulent conditions............................ Mooring ........................................... Rotor blade tiedown procedures ...............
Chapter/Section Number
Page Number
10-00-00 10-00-00
3 3
10-00-00
3
10-00-00 10-00-00
3 4
10-00-00
7
STORAGE 10-8
Storage. .......................................... FIGURES
Figure Number 10-1
Title Parking and mooring.........................................................
Page Number 5
10-00-00 Page 1/2
BHT-212-MM
PARKING AND MOORING 10-1.
PARKING AND MOORING.
10-2.
NORMAL CONDITIONS.
10-4.
NOTE The helicopter shall be moored if wind is expected to exceed 45 knots. If possible, the helicopter should be evacuated to a safe area when wind
NOTE This procedure
to be used when
above condition is knots is 75 knots above 75 condition
forecast wind velocity is less than 20 knots. knots. 1.
Park helicopter on a level surface so load
2.
Retract or remove ground handling
wheels (Chapter 9) to allow helicopter to rest on skid landing gear. 3. Align main rotor blades fore and aft, and tail rotor blades parallel to vertical fin. 4.
Tie down main rotor (paragraph 10-5).
5.
Tie down tail rotor (paragraph 10-7).
6. Disconnect battery. 7.
Tighten friction locks on flight controls.
8. Place all switches to OFF position. Remove external power, if applied. 9. Close all doors, windows, and install all access covers. 10-3. 10-3.
MOORING.
TURBULENT TURBULENT CONDITIONS. CONDITIONS.
expected.
1. spaced tietiewith suitably suitably spaced paved ramp ramp with 1. If If aa paved down rings is available, park helicopter on skid landing gear headed in direction from which highest forecast winds are expected. 2 Secure helicopter to ramp tie-downs. Use cable, rope or manufactured tie-downs at
helicopter jacking tie-down fittings. A clevis
used at each of the four tie-down fittings (3 and 4, figure 10-1) will permit use of larger diameter rope.
3. If suitably spaced ramp tie-downs are not available, park helicopter on an unpaved parking area headed in direction from which
highest forecast winds are expected and retract ground handling wheels. Use mooring anchor or make "dead man" anchors. Moor helicopter as described in step 1. 4. Secure main and tail rotor with tie-down straps. If storage space and time is available, remove main rotor blades and store. Secure main rotor hub to mast to prevent movement on flapping axis. 5.
Install covers on pitot tube and engine
exhausts.
Install inlet covers on engine
induction fairing. NOTE
This procedure to be used when
6. Tighten friction on cyclic and collective controls.
winds are 20 to 45 knots.
7. Close all windows, doors and access 1.
Head helicopter into direction of highest
panels.
forecast winds. 2.
Accomplish paragraph 10-2.
8. Fill fuel tank to capacity with prescribed fuel (Chapter 12). 10-00-00 Page 3
BHT-212-MM 9. Secure all ground handling equipment and other objects which might be blown by high winds.
10-7.
Tail rotor.
CAUTION NOTE After
winds
helicopter
subside,
carefully
inspect
for damage
which may have been inflicted
flyingobjects.
by
DO NOT EXCEED LOAD AND/OR
DEFLECTION LIMITS DURING TIE DOWN PROCEDURES
ROTOR.
FOR TAIL
MAXIMUM
LOAD
ALLOWABLE AT BLADE TIP IS 50
10-5.
ROTOR BLADE TIEDOWN
LBS. LBS.
PROCEDURES. NOTE 10-6.
Main rotor.
1. Engage hook of main rotor tie-down strap (1, figure 10-1) in hole of fitting on end of rotor blade above tailboom. If necessary, the weighted end of tie-down strap can be tossed over blade to bring it down into reach. 2. Secure rotor by firmly cross-tying strap of tie-down around tailboom.
10-00-00 Page
4
Rev. 5
BHT recommends that tail rotor blades be secured when exposed to wind gusts in excess of 45 knots and evacuated to a safe area in wind conditions above 65 knots. Attach web tie-down strap (2, figure 10-1)) to tail rotor and secure to loop provided on side of vertical fin.
BHT-212-MM
1. Main Rotor Tiedown Strap
2. Tail Rotor Tiedown Strap 3. Aft Mooring Fitting (2)
4. Forward Mooring Fitting (2)
212-M-10-1
Figure 10-1.
Parking and mooring
10-00-00 Page 5/6
BHT-212-MM
STORAGE 10-8.
STORAGE..
Refer to BHT-ALL-SPM for storage instructions.
10-00-00 Page 7/8
BHT-212-MM
CHAPTER 11 -
MAINTENANCE PROCEDURES
CONTENTS Paragraph Number 11-1 11-2
PLACARDS AND MARKINGS
Title Placards .......................................... Decals - application ............................
Chapter/Section Number
Page Number
11-00-00 11-00-00
3 3
FIGURES Figure Number 11-1
Title Placards and markings ......................................................
Page Number 5
CONSUMABLE MATERIAL LIST The following consumable materials are required to perform the maintenance procedures within this chapter. ITEM NO.
NOMENCLATURE
CAGE/FSCM/ SOURCE
C-305
Aliphatic Naphtha, TT-N-95, Type II
Commercial
C-306
Toluene, TT-T-548
Commercial
11-00-00 Page 1/2
BHT-212-MM
PLACARDS AND MARKINGS 11-1.
PLACARDS.
NOTE
Decals, stencils, and markings used on Model 212 helicopters are shown on figure 11-1 (sheets 1 through 13). The first part of this illustration shows sections, views, and details on the helicopter. Subsequent parts of the illustration show detail appearance, quantity, and location of each unit by an item number. A heavy black asterisk (*) in front of certain index numbers indicates the item is required by government regulation.
Receiving surfaces shall be nonporous, free of dirt, grease, wax, and other contaminants.
1. Prepare nonmetal painted surfaces rp n l and a p a. Thoroughly clean surfaces with a clean, lint-free cloth dampened with aliphatic naphtha (C-305).
b. Wipe dry with clean, lint-free cloth
NOTE
before naphtha evaporates.
The decals shown in detail views are
2.
typical for helicopters being
Prepare bare metal surfaces as follows:
delivered at the time this manual
was published.
Therefore, the
decals shown may be different than
CAUTION
those originally supplied on any
other particular helicopter.
The
decals shown are, generally, the decal which will be supplied when
WHEN CLEANING BARE METAL SURFACES, ENSURE TOLUENE
replacements
DOES NOT COME IN CONTACT
are ordered.
In all
cases, refer to BHT-212-IPC for
WITH
ordering information and decal part numbers for a particular helicopter. 11-2.
ANY
PAINTED
OR
NONMETALLIC SURFACES. a. Thoroughly clean surfaces with a clean, lint-free cloth dampened with toluene (C-306).
DECALS - APPLICATION.
b. Wipe surfaces dry with clean, lint-free cloths before toluene evaporates.
MATERIALS REQUIRED
3. Apply adhesive backed decals as follows: NUMBER
NOMENCLATURE
C-305
Aliphatic Naphtha
C-306
Toluene
NOTE For best adhesion, apply decals at
temperatures above 60°F (16°C). For application at temperatures
The following requirements and procedures are for the application of decals, both interior
and exterior, of the helicopter.
Decals
described herein are not intended for surfaces
below 60°F (16°C), activate decal adhesive with solvent recommended
by manufacturer or use isopropyl alcohol.
which become heated in excess of 150°F (66°C) or on surfaces exposed temperatures below -20°F (-6.7°C).
to
a. Remove liner from back of decal in one quick, even motion. 11-00-00 Page 3
BHT-212-MM
b. Align decal in correct position, Press one edge to surface by running finger along same edge.
unapplied d.
c.
Hold opposite edge tight and slightly
away from surface.
11-00-00 Page 4
For large decals, rub
portion
to surface with firm,
overlapping strokes using a plastic squeegee. Puncture any blister caused by trapped
air with a pin. Work out air with finger or squeegee pressure.
BHT-212-MM
20
20
212-M-1 1-1-1
Figure 11-1. Placards and markings (sheet 1 of 13)
11-00-00
Page 5
BHT-212-MM
RADIO
CALL
PRI
RADIO CALL PLATE
IN ALTN POSITION MAINTAIN INSTRUENT ACCURACY BY CLOSING WINDOWS VENTS AND TURNING HEATER OFF
*®HEATER STATICSOURCE
*
BAGGAGE FIRETEST SWITCH
ALTN
11-00-00
FUELSYSTEMCAPACITY
*
OPERATIONSLIMITATIONS
OPERATIONS LIMITATIONS (TYPICAL)
212-M-11-1-2
Figure 11-1. Placards and markings (sheet 2)
11-00-00 Page 6
BHT-212-MM
FUELSYSTEM CAPACITY
ON
DEFROST
OFF
HEATSELECTOR
Bell Helicopter A Subsidiary of Textron Inc
BELLINSIGNIA
ILLUMINATEDSIGN
FIREEXTINGUISHER 212-M-11-1-3
Figure 11-1. Placards and markings (sheet 3)
11-00-00 Page 7
BHT-212-MM
CAPACITY FIREEXTINGUISHER(31-043-14CGL)
SERVICE WITH MIL-L-7808 OR MIL-L-23699 OIL
OIL
D0 NOT MIX
SEE FLIGHT MANUAL APPROVEDLUBRICANTS APPROVEDLUBRICANTS
with decal NOTE: Replace decal when changing from lubricating oil MIL-L-7808 to MIL-L-23699.
with decal NOTE: Replace decal when changing from lubricating oil MIL-L-7808 to MIL-L-23699.
SERVICEGEARBOX WITH EXXONTURBO OIL 25 OR AERO SHELL TURBINEOIL 555 DO NOTMIX
OIL COLD
ADD 1 OT SERVICE WITH DOD-L-85734 (AS) AEROSHELL TURBINE OIL 555, EXXON TURBO OIL 25, OR ROYCO OIL 555 DO NOT MIX SEE FLIGHT MANUAL ADD 2 QTS
* COLD ADD 3 QTS
SERVICEWITH MIL-L-7808 MIL-L-23699 DOD-L-85734 (AS) AEROSHELLTURBINE OIL 555 EXXON TURBO OIL 25 OR ROYCOOIL 555 DO NOT MIX SEEFLIGHT MANUAL
ENGINE OIL SIGHT GAGE
212-M-11-1-4
Figure 11-1.
11-00-00 Page 8
Placards and markings (sheet 4)
BHT-212-MM
WARNING HIGH SPEED BLOWER HIGH SPEEDBLOWER
INSTALL SHAFTCLAMPS TO EACH OTHER
INDEXED 90
TORQUE TO 30-35 IN.-LB TORQUELIMITS, TAIL ROTORDRIVE SHAFT CLAMP
CAPACITY
DETAILC DECAL L/H SHOWN (SEE DETAILC) DECAL R/H OPPOSITE LOCATEON CENTERLINEOF TAILBOOM
212-M-11-1-5
Figure 11-1.
Placards and markings (sheet 5)
11-00-00 Page 9
BHT-212-MM
WARNING HIGH SPEED BLOWER HIGH SPEEDBLOWER
STRUCTURAL PANEL
REQUIRED GROUND RUN AND FLIGHT THIS PANEL MUST BE INSTALLEDFOR ALL FLIGHTS
*
STRUCTURALPANELREQUIREMENTS 212-M-11-1-6
Figure 11-1. Placards and markings (sheet 6)
11-00-00 Page 10
BHT-212-MM
LOWERCORNER
LOWERCORNER
VIEW A
EMERGENCY PUSH HERE
EMERGENCY EXIT PUSHWINDOWAT LOWERCORNER
EMERGENCY EXIT PUSH WINDOWAT LOWERCORNER
VIEW B
NOTE
For outside door markings, refer to View A, and for inside door markings for doors with pushout windows, refer to View B. 212-M-11-1-7
Figure 11-1. Placards and markings (sheet 7)
11-00-00 Page 11
BHT-212-MM
DANGER TAIL ROTOR
DECAL 2 REQD IN SPACE (CENTER (SEE DETAIL D)
CENTERLINE WINDOW REF
3.0IN. DETAILD
16.0 IN. CENTERFORE& AFT
VIEW OF RIGHT HAND DOOR LOOKING OUTBOARD LEFT HAND DOOR OPPOSITE
EMERGENCYRELEASE
OPEN OPEN ARROW
212-M-11-1-8
Figure 11-1.
11-00-00 Page 12
Placards and markings (sheet 8)
BHT-212-MM
® EMERGENCYRELEASE
LOCKED DOORLOCK
EMERGENCY EXIT ONLY
DOOR LOCK
FOR RESCUE
PULL EMERGENCY COVER TURN HANDLE AND PULL TO OPEN
DOORLOCK
EMERGENCYRELEASEPROCEDURE
ARROW 212-M-11-1-9
Figure 11-1. Placards and markings (sheet 9)
11-00-00 Page 13
BHT-212-MM
SIX CHARACTER IDENTIFICATION MARKING STENCILS TO BE 16.0 INCHES (406.4 mm) HIGH, 10.7 INCHES (271.78 mm) WIDE EXCEPT THE NUMBER "1" IS TO BE 2.7 INCHES (68.58 mm) WIDE AND THE LETTERS "M" AND "N" ARE TO BE 16.0 INCHES (406.4 mm) WIDE, 2.6 INCHES (66.04 mm) SPACING, CHARACTER THICKNESS TO BE 2.7 INCHES (68.58 mm). FIVE OR LESS CHARACTER STENCILS TO BE 20.0 INCHES (508 mm) HIGH, 13.3 INCHES (337.82 mm) WIDE EXCEPT THE NUMBER "1" TO BE 3.3 INCHES (88.82 mm) WIDE AND THE LETTERS "M" AND "N" ARE TO BE 20.0 INCHES (508 mm) WIDE, 3.3 INCHES (88.82 mm) SPACING, CHARACTER THICKNESS TO BE 3.3 INCHES (88.82 mm). LOCATE WITH TOP OF CHARACTERS NEAR LEFT SIDE CENTER BETWEEN LANDING GEAR CROSS TUBES.
PAINT INTERIOROF THE HELLHOLE WHITE COLOR
TURN AND PULL
EMERGENCYEXIT
MAXIMUM ALLOWABLE BALLAST LEFT SIDE 82 POUNDS
RIGHT SIDE 82 POUNDS PULL
MAXIMUM ALLOWABLEBALLAST
212-M-11-1-10
Figure 11-1. Placards and markings (sheet 10)
11-00-00 Page 14
BHT-212-MM
RIGGING RIVET
a
@
HYD RSVR INSIDE
CLOSEAND OPEN
@
XMSN OIL ACCESS DO NOT MIX
GEAR BOXFILLERCAP ON TOP 212-M-11-1-11
Figure 11-1. Placards and markings (sheet 11)
11-00-00 Page 15
BHT-212-MM RESERVOIR 205-076-058 TOTAL SYSTEM CAP.10 U.S.PTS=4.7
LITERS
PIN LATCH INSPECTION
RESERVOIRCAP.5.3 U.S.PTS=2.5 LITERS REFILL LEVEL CAP.2.5 U.S.PTS=I .2 LITERS USE MIL-H-5606 SERVICE
HYDRAULIC
INSTRUCTIONS
WHEN FLUID LEVEL IS VISIBLE FILL
HOLE
FLUID FIVEEACH SIDE
I
TO OVERFLOW
HYD. SYSTEM SERVICING
CAUTION USE ONLY FREON BASED CLEANERS FOR CLEANING EMERGENCYEXIT (
HYD. SYSTEM RESERVOIRCLEANING
PUSH FOR FUEL
FUELSUMP DRAIN
MAX. ALLOWABLEWEIGHT
UR D DOOR LOCK
GROUND HERE 212-M-11-1-12
Figure 11-1.. Placards and markings (sheet 12)
11-00-00 Page 16
BHT-212-MM
F
SSTE
CAIPACBTY M
20U.S.G 4
FUEL SYSTEMCAPACITY
45 I AU
® RIGGINGRIVET
RIGGING RIVET 212-M-11-1-13
Figure 11-1.
Placards and markings (sheet 13)
11-00-00 Page 17/18
BHT-212-MM
CHAPTER 12 CONTENTS Paragraph Number 12-1 12-2 12-7 12-12 12-13 12-14 12-15 12-16
SERVICING
MAINTENANCE PROCEDURES
Title Servicing ......................................... Fuel system .................................... Oil system ...................................... Main rotor hub ................................. Stabilizer bar dampers ......................... Hydraulic systems .............................. Battery ......................................... Fire extinguishers ..............................
Chapter/Section Number
Page Number
12-00-00 12-00-00 12-00-00 12-00-00 12-00-00 12-00-00 12-00-00 12-00-00
3 3 10 11 11 11 12 12
12-00-00 12-00-00 12-00-00 12-00-00
13 13 13 13
LUBRICATION 12-19 12-20 12-21 12-22
Lubrication ........................................ Lubrication symbols ............................ Lubricant, 204-040-755-005, restrictions ....... Flexible coupling lubrication log................ FIGURES
Figure Number 12-1 12-2
Title Servicing points......... ..................................................... Lubrication chart. ............................................................
Page Number 7 15
TABLES Table Number 12-1 12-2
Title Servicing materials and capacities ........................................... Flex couplings lubrication log (EXAMPLE ONLY) ............................
Page Number 4 14
12-00-00 Page
1
BHT-212-MM
CONSUMABLE MATERIAL LIST The following consumable materials are required to perform the maintenance procedures within this chapter. ITEM
NO.
C-009
12-00-00 Page 2
CAGE/FSCM/
NOMENCLATURE
Lubricating Oil, Grade 1010, MIL-L-6081
SOURCE
Commercial
BHT-212-MM
SERVICING 12-1.
SERVICING.
12-3.
Refueling/defueling preparation.
CAUTION
WARNING
STAINED OR DISCOLORED SIGHT GAGE GLASSES MAY GIVE FALSE
FUELING REQUIRES
INDICATION OF OIL/FLUID
ON THE
QUANTITY.
PERSONNEL.
IF FALSE INDICATION
IS SUSPECTED,
SHAKE
AND DEFUELING EXTREME CAUTION
PART
OF ALL
THE FUELS USED
ARE EXTREMELY FLAMMABLE
HELICOPTER BY TAIL SKID AND OBSERVE OIL/FLUID MOVEMENT.
AND EASILY IGNITED. FUEL VAPORS CAN BE IGNITED BY
REPLACE ANY SIGHT GAGE GLASS WHICH DOES NOT PROVIDE ADEQUATELY CLEAR
STATIC OR FRICTION SPARKS, HOT EXHAUST PIPES, LIGHTED CIGARETTE, ELECTRICAL
INDICATION OF OILFLUID LEVEL.
This Chapter contains instructions
to
DEVICES, AND SIMILAR IGNITION SOURCES.
replenish fuel, lubricating oil, hydraulic fluid, and to lubricate the helicopter. Defueling and
PERSONNEL SHOULD ABOARD HELICOPTER
fuel cell purging are also included.
F U E L I N G / D E F U E L I N G
Figure 12-1 identifies servicing points, defueling, and drain valve locations.
Table
12-1 specifies useable materials for fuel, lubricating oil and hydraulic fluid. 12-2.
FUEL SYSTEM.
NOT BE DURING
PROCEDURES. WHEN HELICOPTER FUEL COMES
INTO CONTACT WITH SKIN. A SOLVENT ACTION OCCURS
WHICH REMOVES NATURAL FATS AND OIL WHICH MAY EXPOSE
SKIN TO INFECTIOUS
All five interconnected cells of the main fuel system are serviced through a single filler located on right side of the helicopter. A
DERMATOSES. EXTENSIVE VAPOR INHALATION MAY CAUSE SERIOUS ILLNESS. ACCIDENTAL
grounding jack is provided near the filler.
SWALLOWING OF FUELS WILL
Sump drains are located in the bottom of right
RESULT
and left fuel cells beneath the cabin floor.
AND
System defuel valves are accessible through the bottom skin behind aft cabin bulkhead. A system filter is located ahead of each of the two engine power sections. The filters are connected to the caution panel for indication of impending bypass condition.
PERSONNEL SUBJECTED TO SPLASHED OR SPRAYED FUEL SHOULD REMOVE CONTAMINATED CLOTHING AS SOON AS POSSIBLE AND WASH DOWN/ SHOWER WITH LARGE AMOUNTS OF WATER. DO NOT REMOVE
IN INTERNAL
POSSIBLY
INJURY
DEATH.
CLOTHING NEAR POTENTIAL IGNITION SOURCES.
1. Allow only qualified personnel actually engaged in fueling/defueling operations in the area. Allow no one to carry matches, lighters, or other sparking or flame-producing devices in the area. 12-00-00 Page 3
BHT-212-MM
2. Do not perform fueling/defueling when high winds are considered hazardous or when electrical storms are within a three mile (five
11. One fully-charged, 50 lb. (22.68 kg) C02 fire extinguisher, equipped with an extension assembly, shall be immediately accessible.
kilometer)
Access to fire extinguishers on vehicles shall
radius of fueling or defueling
operations. 3.
not be obstructed.
Fuel transfer
personnel
shall not wear
12.
A minimum of 20 feet (6.096 meters)
static producing clothing such as nylon,
shall be maintained from other aircraft by
rayon, or wool. operations, all helicopter should gripping the static
servicing units during fueling or defueling. All venting doors on servicing unit shall be open.
be worn,
and reason other than fueling, grasp
4. Do not perform perform fueling/defueling fueling/defueling
receptacle) with bare hands to dissipate any
Before starting actual fuel persons working at the dissipate static potential by ground line with bare hand. Shoes with taps or protruding nails should should not not
operations
13.
If fuel cell filler cap is to be removed for
helicopter grounding jack (adjacent to filler near drainage
ditches
or low
static charge prior to
moving cap.
places where combustible vapors could accumulate.
5.
Do not perform
CAUTION
fueling/defueling
operations in a hangar.
6. During fueling or defueling, helicopter
shall be positioned at least 50 feet (15 meters) away from any building or smoking
7.
The helicopter shall be positioned at least
500 feet (152.4 meters) from any radar
ACCOMPLISH
GROUNDING
PROCEDURES
IN THE
FOLLOWING STEPS IN ORDER
LISTED
TO REDUCE
THE
POSSIBILITY OF STATIC ELECTRICITY CAUSING FUEL TO IGNITE.
14. Ground fuel/defuel
vehicle
and
helicopter as follows prior to removing fuel
8.
Do not perform fueling/defueling
operations when other aircraft are operating
hose filler dust cap and/or helicopter fuel cell filler cap or prior to using defueling valve.
within 100 feet (30.48 meters) of refueling area.
a. Ground fueling vehicle to an approved static ground rod with a grounding cable.
9. Position servicing unit as far from helicopter as hose will permit, and in a position so it may be driven or towed away from the area in event of an emergency. Set parking brake.
b. Ground helicopter to an approved static ground rod with a grounding cable.
10. Clear paths shall be maintained around
for grounding plug, use plug; if not, clip
the helicopter being serviced to permit rapid evacuation of vehicles and personnel.
alligator clip to a bare metal part of helicopter.
12-00-00 Page 4
c. Ground fuel hose nozzle to helicopter grounding jack. If helicopter has a receiver
BHT-212-MM
Table 12-1. NAME
MATERIAL SPECIFICATION
Servicing materials and capacities GRADE
CAPACITY
REMARKS
JP-4
217.0 Gals.
All ambient temperatures.
JP-5
217.0 Gals.
All temperatures above -22°F (30°C).
MAIN FUEL SYSTEM Turbine Fuel
Refer to BHT212-FM
Turbine Fuel
ENGINE OIL SYSTEM -1.60
Gals.
Left power section. Do not mix oils.
Lubricating oil
-1.60
Gals.
Right power section. Do not mix oils.
Lubricating oil
-1.25
Gals.
Combining gearbox. Do not mix oils
Lubricating oil
Refer to BHT212-FM
TRANSMISSION OIL SYSTEM Lubricating Oil
11.0 Qts
Do not mix oils.
Refer to BHT212-FM
-
Refer to BHT212-FM
-0.19
Qt
Do not mix oils.
-0.40
Qt
Do not mix oils.
GEARBOXES: INTERMEDIATE GEARBOX Lubricating Oil
TAIL ROTOR GEARBOX Lubricating Oil MAIN ROTOR HUB BLADE GRIPS Lubricating Oil
Refer to BHT212-FM
-1.0
Qt per grip
Do not mix oils.
PILLOW BLOCKS 12-00-00 Page 5
BHT-212-MM
Table 12-1.
Servicing materials and capacities (Cont)
NAME
MATERIAL SPECIFICATION
Lubricating Oil
Refer to BHT212-FM
GRADE
CAPACITY
REMARKS
0.12 Qt per block
Do not mix oils.
HYDRAULIC SYSTEMS SYSTEM
1
4.7 Qts
-
Refer to BHT212-FM
Hydraulic Fluid SYSTEM 2 Hydraulic Fluid
4.25 Qts
Hydraulic Fluid Reservoirs
2.64 Qts per reservoir
ROTOR BRAKE SYSTEM 1.00 Pint
Refer to BHT212-FM
Hydraulic Fluid
Position fire extinguishers.
8.
Ground servicing
9.
Ground helicopter to approved grounding
All helicopter electrical power shall be
15.
OFF. 12-4.
unit to approved
grounding rod. Fueling.
1. Comply with requirements of paragraph 12-3. 2.
7.
Ensure helicopter electrical power is off.
If electrical power is required, turn battery
rod.
10. Attach transfer hose nozzle ground wire to helicopter.
11. Remove filler cap.
switch(es) on and position remaining switches
as required
operations.
before commecing
fueling
Do not accomplish further
12. Service fuel cells slowly.
switching until fueling is complete except in an emergency situation. 3.
Check vent lines for obstructions.
4.
Move servicing unit into position.
5.
Park servicing unit and set brake.
6. Check fuel in servicing correct right type. 12-00-00 Page 6
unit to ensure
CAUTION
DO NOT LEAVE
NOZZLE
AT ANY TIME UNATTENDED DURING REFUELING OPERATION. 13.
Replace filler cap and nozzle dust cap.
BHT-212-MM
GEARBOX OIL FILLER AND GAGE
PILLOW BLOCK OIL RESERVOIR
HUB GRIP OIL RESERVOIR GEARBOX OIL FILLER AND GAGE
MAIN ROTORHUB
TRANSMISSION OIL FILLER
\
r
HYDRAULIC RESERVOIRS
COMBINING GEARBOX FILLERAND GAGE
HYDRAULIC HYDRAULIC FILTERS
ENGINEFIREEXTINGUISHER R.H. ENGINE OIL FILTERAND GAGE
ROTOR BRAKE
STEPS
BATTERY BATTERY
FUELTANK FILLER TRANSMISSION OIL FILTER,GAGES, AND DRAIN GROUNDINGJACK FUEL SUMP DRAINS (EACH SIDE)
NOTE After compliance with TB212-81-56, refer to lubrication chart, figure 12-2.
STEPS STEP POWER
RECEPTACLE ENGINE FIREEXTINGUISHER L.H. ENGINE OIL FILLERAND GAGE STEPS GROUNDING JACK HYDRAULIC TEST COUPLINGS AUXILIARY FUEL TANK CONNECTIONS(EACH SIDE) TRANSMISSION OIL COOLERDRAINVALVES DEFUELVALVE (EACH SIDE)
212-M-12-1
Figure 12-1. Servicing points
12-00-00 Page 7
BHT-212-MM
14. Battery and required system switches
switching
OFF, if required (BHT-212-FM).
defueling is complete except as required by an emergency condition.
15.
Remove transfer nozzle ground wire.
16.
Remove helicopter ground.
17.
Remove service unit ground.
18. In the event of a fire emergency, accomplish the following as quickly as possible.
shall
be done until
4.
Check vent lines for obstructions.
5.
Move servicing unit into position.
6.
Park servicing unit and set brake.
7. Position fire extinguishers.
8. Ground servicing unit to approved a.
Stop fuel flow.
grounding rod.
b.
Separate helicopter and service unit.
9. Ground the helicopter grounding rod.
c.
Sound alarm.
d.
Attempt rescue and contain fire.
12-5.
to approved
10. Attach defueling tube/hose ground wire to the helicopter. 11. Remove filler cap.
Defueling.
12.
Insert defueling tube/hose into helicopter
CAUTION 13. Start pumping fuel from helicopter.
IF HELICOPTER
IS BEING
BECAUSE
DEFUELED
OF
A
CRASH, FORCED LANDING, OR 0 F F U EL I S QUALITY QUESTIONABLE, FUEL DRAINED SHOULD BE STORED, SAMPLED,
AND TESTED
BEFORE
USE,
14. As fuel flow stops, shut down pump.
15.
tube/hose
Remove defueling
from
helicopter.
16. Replace filler cap.
DOWNGRADED, OR DISPOSED OF A S
T E S T S
I N D I C AT
E
17.
1. Comply with requirements of paragraph 12-3.
defueling
tube/hose
ground
18. Remove helicopter ground. 19.
2.
Remove
wire and reel tube/hose up.
APPROPRIATE.
Remove service unit ground.
Notify fire department of defueling
operation location, anticipated start time, and estimated time of completion.
CAUTION
3. Check all helicopter electrical power is OFF.
DO NOT RETURN DRAINED FUEL TO A STORAGE AREA UNLESS IT IS PASSED THROUGH A FILTER/ SEPARATOR AS IT IS DRAINED FROM HELICOPTER.
NOTE If power is required, turn battery and
required switches ON prior to defueling 12-00-00 Page 8
operation.
No further
20.
Purge fuel system (paragraph 12-6).
BHT-212-MM
21. In the event of a fire, accomplish the following as quickly as possible. a.
Stop fuel flow.
b.
Separate helicopter and service unit.
c.
Sound alarm.
d.
Attempt rescue and contain fire.
WARNING EXPLOSIMETER READING SHALL BE LESS THAN 20%. IF READING
IS MORE THAN 20%, REPEAT STEPS a. THROUGH c. UNTIL READING IS LESS THAN 20%.
e. Check interior of fuel cell with explosimeter (combustible gas indicator calibrated for fuel vapors) for level of fuel
12-6. Purging.
vapors. MATERIALS REQUIRED NUMBER
NOMENCLATURE
C-009
Lubricatina Oil
ON A STILL
1.
Prepare helicopter
CONDITION)
for defueling
ACCUMULATE
(paragraph 12-3). 2.
DAY (NO WIND FUEL VAPOR CAN
IN AREA OF
HELICOPTER (EVEN IN AN OPEN AREA). UNDER THIS CONDITION, PERSONNEL SHOULD BE
Defuel helicopter (paragraph 12-5).
CLEARED
FROM AREA EVEN
INSTALLED
AND INERT GAS IS
AFTER WARNING
PURGE LINES ARE
FLOWING UNTIL EIGHT HOURS OF PURGING IS COMPLETED.
USE DRY,
FILTERED,
COM-
PRESSED AIR AS DESCRIBED IN
4.
STEP
inert (nitrogen) gas as follows:
3.
OR
(NITROGEN
INERT
GAS
OR CARBON
Purge cells using carbon dioxide (C02) or
DIOXIDE) AS OUTLINED IN STEP 4. -WARNING 3.
Compressed air purge fuel cell as follows: a.
Open all sump drains and drain lines.
b.
Insert compressed air hose in cell filler
inlet, under cap and seal opening with masking tape.
c. Blow filtered, compressed air through cells at 60 to 100 psi for a period of eight
hours.
d. Remove compressed air hose from cell inlet. Wait one hour.
REMOVE FIBER HORN WHEN USING A FIRE EXTINGUISHER BOTTLE AS A SOURCE OF C02 FOR PURGING FUEL CELLS.
GROUND NOZZLE TO HELICOPTER.
DISCHARGE INERT
GAS INTO FUEL CELL SLOWLY AT A RATE OF ONE POUND PER MINUTE. RAPID PASSAGE OF
GAS THROUGH A HOSE CAN GENERATE STATIC ELECTRICAL CHARGES. RAPID DISCHARGE OF THE GAS ALLOWS RAPID
EXPANSION LOWERING
OF THE GAS,
THE TEMPERATURE
WITH POSSIBLE
DAMAGE TO 12-00-00 Page 9
BHT-212-MM
CELL AS A RESULT. NITROGEN GAS OR OTHER INERT GAS MAY
555 oil in intermediate and tail rotor gearboxes (BHT-212-FM).
BE USED WITH THE SAME PRECAUTIONARY OUTLINED ABOVE.
MEASURES
Open all sump drains and drain lines,
a.
b. Insert inert gas hose in cell filler inlet and seal with masking tape. c. Blow inert gas through cells for a period of eight hours.
It is recommeded when systems are serviced, either for an oil change or routine quantity servicing, the oil container be agitated prior to is If oil pressure fluctuation opening. accompanied by foaming, drain and service with agitated oil. When using quart cans, open end which has been on bottom during storage. 12-8.
Changing oil brands or type.
d. Remove inert gas hose from cell inlet. Wait one hour.
NOTE An appropriate entry shall be made in helicopter and engine logbooks. The entry shall show type and brand name of oil to prevent inadvertent mixing of lubricating oils. Refer to engine manufacturers manual for additional information, and oil change intervals for the engine.
WARNIN
EXPLOSIMETER READING SHALL BE LESS THEN 20%. IF READING IS MORE THAN 20%, REPEAT
STEPS b. THROUGH d. UNTIL READING IS LESS THAN 20%.
NOTE
e. Check interior of fuel cell with explosimeter (combustible gas indicator calibrated for fuel vapors) for level of fuel
Do not use MIL-L-23699 or ASTO 555 (DOD-L-85734) lubricating oil when ambient temperature falls
vapors.
below -40°F (-40°C).
5. Fog interior of fuel cell with lubricating oil (C-009). Close drains and replace filler cap. Do not close vents. 12-7.
OIL SYSTEM.
The engine, transmission, tail rotor drive
1. Before changing types oil from 7808 to MILL23699, or to of ASTO 555 MIL-L(DODL-85734), replace decals shown in Chapter 11, with appropriate decals denoting type of oil in system.
2.
If oil brand change
is made after
hub may be
extended time on one oil, it is recommended
serviced with MIL-L-7808, MIL-L-23699, or
system be flushed and a filter inspection
Turbine Oil 555 lubricating oil. Refer to BHT-
accomplished after five and fifteen hours of
and main
gearboxes
212-FM
rotor
for list of approved
oils
and
operation on new oil for accumulation of filter deposits.
restrictions. NOTE
NOTE
Transmissions modified to P/N 212040-001-131 require ASTO 555 oil or MIL-L-7808 oil only. Helicopters
MIL-L-7808, MIL-L-23699, or ASTO 555 (DOD-L-85734) lubricating oils should not be mixed. If this should
using
212-040-001-131
occur, drain system and refill with
may also use ASTO
approved oil.
P/N
transmission 12-00-00 Page 10
BHT-212-MM
3. To change oil type, perform the following steps:
Engine oil system maintenance practices are contained in Chapter 79.
a. Drain lubricating oil from system.
Inspect and clean filter and strainers as required. b. b.
The transmission sump case serves as the
Fill Fill oil oil system system with with specification specification lubricating to be used. oil
of of
and is accessible when the forward pylon
minutes to one hour to heat oil to operating
temperature. Shut down engine. d. clean system system oil d. Inspect Inspect and and clean oil filters filters and and strainers. If heavy contamination of filters and is strainers noted proceed with steps and strainers is noted, proceed with steps e e. through
filters
h.
If little or no contamination
and strainers
is noted,
of
release
helicopter for service and proceed with steps g. and h. e. Drain lubricating oil from oil system and discard oil. f.
Refill oil system with specification
lubricating
reservoir for this system. The filler is located on the upper right side of the transmission
of
structure in cabin with aid of a light controlled
structure in cabin with aid of a light controlled is located directly beneath the sump. An external filter, in return line from oil cooler, is
located inside pylon which structure sidewhen and has a red indicator will at beright visible filter is in impending bypass
condition.
Drain
valves in oil collector lines are accessible
through bottom fuselage skin inboard of F.S. 169.0. Refer to table 12-1 for list of approved
oils and for location of filler.
Maintenance
practices are contained contained in 63. practices are in Chapter Chapter 63. 12-11.
Tail rotor gearboxes.
oil to be used and release
helicopter for service.
Oil level in the intermediate
and tail rotor
gearboxes may be checked on the sight g. Inspection and cleaning of oil system filters and strainers is required after five and fifteen hours of operating time.
h. After fifteen hour inspection of oil
gages and replenished, as required. Intermediate gearbox and tail rotor gearbox maintenance practices are contained in
Chapter 63. Refer to table 12-1 for list of approved oils.
system filters and strainers, revert to normal inspection interval.
12-12.
12-9.
Transparent plastic sight gages are on grip
Engine oil system.
MAIN ROTOR HUB.
and pillow block reservoirs for checking oil The engine assembly has three independent oil systems, each with its own filler and oil level sight gage. Fillers and gages for left and right engine power sections are outboard
level. Oil level shall be maintained at onehalf indication.
accessible by opening engine cowling.
Check timing Check timing and and service service only only as as necessary necessary
of the accessory gearboxes and are
The
third gage is on the aft side of reduction gearbox, with access through aft right engine
cowl below exhaust ejectors.
STABILIZER BAR DAMPERS.
(Chapter 62).
The third
system oil filler is located in aft top fairing
between exhaust ejectors.
12-13.
12-14.
HYDRAULIC SYSTEMS.
The third oil
system cooler and strainer may be drained by opening drain valve located on engine deck. Avoid excessive oil spillage if chip detector plug is removed to completely drain system.
Access to hydraulic reservoirs is opening forward pylon fairing. reservoir is on right side and reservoir is on left side. Pressure
gained by System 1 system 2 and return 12-00-00 Page 11
BHT-212-MM
filters, with red pop-out indicators which will
12-15.
BATTERY.
be visible when filter requires change, are valve and filter in integrated located assemblies in pylon. System 1 integrated
The nickel cadmium battery is located in the helicopter nose compartment. Refer to BHT-
valve and filter assembly is located at lower
ALL-SPM
front center of lift beam. System 2 integrated valve and filter assembly is aft of lift beam on left side of pylon.
maintenance.
manual
for
servicing
and
12-16.
FIRE EXTINGUISHERS.
through an access door on forward side of pylon structure. A supplemental indicator is
12-17.
Engine fire extinguisher bottles.
located to right of helicopter centerline at
Check gages of engine compartment fire
W.L. 22.00, and is visible through lower right
extinguisher bottles through inspection door in
Filters may be checked from inside cabin
nose window. hydraulic
circuit
With engine running and breakers
closed, a green
indication verifies systems are operating without clogging. clogging. Under the same same without Under the circumstances, a red indication warns there is an impending bypass condition. Rotor brake hydraulic system is a separate
self-contained system. See figure 12-1 for location of filler, and table 12-1 for approved
lubricating fluids.
12-00-00 Page 12
sides of engine cowling.
If gage is below
acceptable limit, refer to Chapter 26.
12-18. Portable fire extinguishers. Check gages of portable fire extinguishers in
cabin 26). (Chapter 26). cabin (Chapter
BHT-212-MM
LUBRICATION 12-19.
LUBRICATION.
The lubrication chart (figure 12-2) illustrates
1. Lubricant, 204-040-755-005, lubricant (tube pack) (C-015) shelf life is 4 years from packing date on container.
each area which requires lubrication with grease-type lubricant. The legend of this
2.
illustration lists items to be lubricated. 1.
After each day of operation in rain, snow,
or after washing helicopter,
In-stock components which utilize 204-
040-755-005 lubricant must be pulled from stock and and relubricated upon expiration of the original 4-year shelf life of the lubricant.
all exposed
control bearings should be purge-lubricated to remove trapped moisture and ensure a lube
3. Once a component lubricated with 204040-755-005 lubricant goes into service, the
film is applied to susceptible surfaces.
relubrication
2.
interval is dictated by the
Parking helicopters outside in a heavy
calendar and service-time schedule whether the component is installed on a helicopter or
dew environment requires that all exposed
is subsequently removed and returned to
every control bearings be purge-lubricated seven days to ensure that no voids exist that
stock as a spare on the shelf.
could trap moisture.
4.
3. If helicopter is stored for periods in excess of 45 days without operation or
lubricant should be stored at moderate ambient temperatures, preferably less than
service, purge-lubricate all bearings.
80°F(26.7°C). Elevated storage temperatures promote oil separation from the lubricant.
12-20.
LUBRICATION SYMBOLS.
The lubrication
Lubricant
in original
tubes
and
components containing 204-040-755-005
12-22.
chart uses symbols and
FLEXIBLE COUPLING
LUBRICATION LOG.
abbreviations to indicate the required lubricant,
method of application,
and time
MATERIALS REQUIRED
interval for lubrication of each component listed. A key on the chart indicates meaning of symbols and abbreviations.
12-21.
LUBRICANT, 204-040-755-005,
RESTRICTIONS.
MATERIALS REQUIRED MATERIALS REQUIRED Refer to BHT-ALL-SPM for specification and source.
Refer to BHT-ALL-SPM for specification and source.
NUMBER
NOMENCLATURE
C-015
Lubricant (Tube Pack)
A flex coupling lubrication log similar to one shown on table 12-2 shall be maintained any time a component using lubricant (tube pack) (C-015) is installed on the helicopter. This log
was applied
in
NUMBER
NOMENCLATURE
shall list date lubricant
C-015
Lubricant (Tube Pack)
operational hour and a calendar requirements specified in this chapter. Lubricant shall be replaced at requirement occurring first (hours/ months).
NOTE
component.
This lubricant carries an
Do not exceed lubrication intervals specified on lubrication chart. 12-00-00 Rev. 5
Page
13
BHT-212-MM
Table 12-2. PART NUMBER
Flex couplings lubrication log (EXAMPLE ONLY)
NOMENCALTURE
DATE LUBRICATED
AIRFRAME HOURS
DATE LUBRICATED
AIRFRAME HOURS
Main Driveshaft
Transmission Tail Rotor Drive Output Coupling
Tail Rotor Driveshaft Hanger (8)
Intermediate Gearbox Input Quill
Intermediate Gearbox Output Quill
Tail Rotor Gearbox Input Quill
(TABLE I.D. 911246)
12-00-00 Page 14
BHT-212-MM
25 HOURS
LUBRICANTS
SYMBOLS
50 HOURS 100 HOURS
Grease Gun
Symbol
Specification
(Hand Type)
GAP
MIL-G-25537
Hand
204-040-755-005 GWT
300 HOURS
SEE DETAILD AND E
MIL-G-81322
MAIN DRIVESHAFT COUPLING 212-040-005, 212-040-005-003,-007. -001 and-011
600[HOURS
and -103 -103
1000 HOURS SIXMONTHS
SEE DETAILC
212-M-12-2-1
Figure 12-2.
Lubrication chart (sheet 1 of 4)
12-00-00 Page 15
BHT-212-MM
1. Axle pivot point
G
2. Actuating cylinder trunnions 3. Wheel bearings 4. Pin assembly
5. Securing pin 6. Collective sleeve bearing 7. Scissor bearings 8. Swashplate bearings
9. Collective lever trunnion 10. Outer control plate trunnions 11. Control plate trunnions
12. Scissors pivot cover plate 13. Collective sleeve splines 14. Scissors pivot needle bearing (P/N 212-010-407 Scissors)
5
4
15. Crosshead bearing 16. Antitorque control lever
GAP
17. Pitch change link universal
TWO PLACES
18. Stabilizer centerframe bearing 19. Mixing lever bearings 20. Trunnion bearing
TWO PLACES
GP TWO PLACES
DETAILA
21. Link assembly
FOUR PLACES
TWO PLACES
THREE PLACES
DETAIL B
Figure 12-2. Lubrication chart (sheet 2)
12-00-00 Page 16
Rev. 5
TWO PLACES
212-M-12-2-2
BHT-212-MM
212-010-701 HUB AND BLADE -
DETAIL D
TWO PLACES EACH SIDE
ONE PLACE
212-M-12-2-3
Figure 12-2.
Lubrication chart (sheet 3)
12-00-00 Page 17
BHT-212-MM
VIEW A-A
HUB AND BLADE PIN 212-011-701
DETAIL E
NOTES MIL-G-81322 grease is recommended for use in all applications which previously used MIL-G-25537
Lubricate couplings on P/N 212-040-005-003, -007, and -103 main driveshaft ever 600 hours or 12
grease; however, intermixing of grease is prohibited. When changing from one greaseto the other, purge until previous grease is depleted. Exercise same care when switching brands of
months; whichever occurs first.
grease as when switching types of grease.
Lubricate tail rotor driveshaft couplings ever 600 hours or six months; whichever occurs first. A
Lubricate more frequently If conditions warrant.
as when switching Lubricate hanger bearing by slowly pumping
Purge lubricate.
grease into fitting until grease may be seen around bearing seal. Use caution because excessive pump pressure may push seal from bearing.
Do not overlubricate
bearing. Two
considered adequate.
Lubricate tall rotor hanger bearing with Mobil 28
conforming to MIL-G-81322grease.
crosshead
shots of grease each 50 hours of operation is A If T.B. 212-81-56 has been complied with, purge
lubricate main rotor grips and trunnions with MIL-G-81322each 50 hours of operation. Refer to T.B.212-81-56for lubrication Instructions.
main Lubricate couplings on P/N 212-040-005-011 driveshaft ever 300 hours or 3 months; whichever occurs first.
Lubricate until grease passes seal.
Grease, 204-040-755-5, has a shelf storage life of
4 years whether stored In original container or in a component. If a component is not put in service
prior to expiration of the 4 year shelf life of the grease, component shall be relubricated prior to installation on a helicopter. After initial operation of component on the helicopter, refer to lubrication chart for lubrication intervals.
A Every 4th 25 (100 hours) rotate bearing 180° and
purge lubricate (Chapter 5). Lubricate lever assembly P/N 209-011-712-101 every 50 hours of operation. 212-M-1 2-2-4
Figure 12-2. Lubrication chart (sheet 4)
12-00-00 Page 18
Rev. 5
BHT-212-MM CHAPTER 18 - VIBRATION AND NOISE ANALYSIS CONTENTS Paragraph Number 18-1
MAINTENANCE PROCEDURES
Title General...........................................
Chapter/Section Number
Page Number
18-00-00
5
ROTOR SMOOTHING AND VIBRATION ANALYSIS 18-2 18-3 18-8 18-9 18-10
Vibration analysis ................................. Main rotor ...................................... Tail rotor. ...................................... Other vibrations ............................... Troubleshooting ...............................
18-00-00 18-00-00 18-00-00 18-00-00 18-00-00
5 5 8 8 8
18-00-00
9
18-00-00 18-00-00 18-00-00
9 10 10
ROTOR TRACKING AND BALANCING 18-11 18-12 18-13 18-14
Main rotor tracking ............................... Main rotor blade vibration check and adjustment. .................................... Blade sweeping ............................... Autorotation rpm adjustment ..................
ROTOR TRACKING AND BALANCING SCIENTIFIC ATLANTA ROTOR ANALYSIS AND DIAGNOSTIC SYSTEM, MODEL AT (RADS AT) 18-15 18-16 18-19 18-23 18-24 18-25 18-26
Main rotor tracking and balancing ............... Rotor vibration measurement instrumentation................................. Main rotor 2/REV check (optional). ............ Span balance adjustment - RADS AT .......... Sweep adjustment - RADS AT ................. Pitch link adjustment - RADS AT............... Outboard trim tabs adjustment - RADS
AT......... 18-27 18-30 18-33 18-34 18-36 18-39 18-40 18-45
.......
........................
General vibration check (optional) RADS AT ................ ............. ........ Vibration troubleshooting (optional) .............................. RADS AT ......... Tail rotor - tracking and balancing................ Tail rotor vibration measurement
instrumentation..
.........
.
Test to balance tail rotor ...................... Main driveshaft balancing. ....................... Driveshaft vibration measurement instrumentation ............................ General vibration check (optional) RADS AT .......................................
..
18-00-00
15
18-00-00 18-00-00 18-00-00 18-00-00 18-00-00
15 28 32 36 36
18-00-00
37-
18-00-00
37
18-00-00 18-00-00
40 41
18-00-00
41
18-00-00 18-00-00
42 52
18-00-00
52
18-00-00
59 18-00-00
Rev. 5
Page
1
BHT-212-MM CONTENTS Paragraph Number
18-46
MAINTENANCE PROCEDURES (Cont)
Title
Chapter/Section Number
Page Number
18-00-00
59
Vibration troubleshooting (optional) RADS AT.......................................
FIGURES Figure Number
Page Number
Title
18-1 18-2 18-3 18-4
Main rotor tracking .................................................... Lateral vibration troubleshooting ...................................... Rotor smoothing ....................................................... Trim tab bender and gage ............................................
11 12 13 14
18-5
Accelerometer locations .........
17
18-6 18-7 18-8 18-9 18-10 18-11 18-12 18-13 18-14 18-15 18-16 18-17 18-18 18-19 18-20 18-21 18-22 18-23 18-24 18-25 18-26 18-27 18-28 18-29 18-30 18-31
Main rotor - proper RADS AT installation ............................. Magnetic pickup and interrupter ...................................... Passive optical tracker location and cable routing .................... Optical tracker angle .................................................. Location of paint and tape for tracking ................................ Main rotor smoothing CADU screen ................................... ................... Model 212 main rotor adjustment log ......... RADS AT proper configuration (2/R-CHK) ............................ Main rotor smoothing CADU screen (2/R-CHK) ....................... Model 212 main rotor adjustment log (2R/-CHK) ...................... ............................ Main rotor adjustments ................. RADS AT proper configuration (VIBCHK) ............................. Main rotor smoothing CADU screen (VIBCHK) ........................ Main rotor smoothing CADU screen (Spectrum) ....................... Excitation frequencies ................................................. Accelerometer and optical sensor installation - Tail rotor ............. ................. Tail rotor - proper RADS AT installation ......... Tail rotor smoothing CADU screen ................................... Tail rotor adjustment log .............................................. Tail rotor balance hardware ........................................... Combining gearbox and transmission input quill accelerometer....... Optical rpm sensor and bracket ....................................... Reflective tape installation, main driveshaft ........................... RADS AT configuration for balancing main driveshaft................. Main driveshaft balancing CADU screen .............................. Main driveshaft adjustment log ........................................
18-00-00 Page
2
Rev. 5
... ............................
18 19 20 21 23 24 25 31 32 33 34 39 42 43 44 46 47 49 50 51 54 55 57 58 59 60
BHT-212-MM TABLES Table Number
Page Number
Title
18-1 18-2
Test condition - Main rotor ............................................ Vibration criteria - Main rotor ..........................................
26 27
18-3
Troubleshooting .......................................................
29
18-4 18-5 18-6 18-7 18-8 18-9
Accelerometer location, channel and installation ...................... Test condition (VIBCHK) - Main rotor ................................. Vibration source - Main rotor .......................................... Vibration source - Tail rotor ........................................... Balancing hardware - Tail rotor ....................................... Vibration source - Driveshaft ..........................................
35 35 38 48 52 61
Rev. 5
18-00-00 Page 3/4
BHT-212-MM
VIBRATION AND NOISE ANALYSIS 18-1.
For convenience, balancing of the tail rotor and main driveshaft are also included in this
GENERAL.
This chapter
provides
and
information
procedures required to maintain helicopter with respect to quality of the ride and control
chapter. Maintenance procedures for these components will be found in the appropriate chapters.
of rotating component generated vibration. The instrument recommended to support the Model 212 is the Scientific Atlanta RADS AT.
ROTOR SMOOTHING AND VIBRATION ANALYSIS.
actually
18-2. VIBRATION ANALYSIS. 18-3.
NOTE Refer to Chapter 62 for the complete field maintenance instructions for the main rotor and rotating control components. are always present
and
divided in general frequencies as follows:
MAIN ROTOR
Most vibrations
it is not. For simplicity
standardization, vibrations are arbitrarily
in the
Extremely low frequency
Less than 1/rev pylon rock
Low frequency r
1/rev or 2/rev type rv r rv vibration Generally, or 6 4, 5, 5, or 6/ Generally, 4, rev
Medium frequency Medium frequency High frequency
helicopter at low magnitudes. The main problem is deciding when a vibration level has reached the point of being unacceptable. The only sources of any frequency are rotating or moving parts on the helicopter. Other parts
Tail rotor or faster
(buzz)
18-4.
Extreme low frequency.
vibrate only in sympathy with an existing vibration. Extreme low, low frequency, and most medium frequency vibrations are caused by the rotor or dynamic controls. Various malfunctions in stationary components can
Extreme low frequency vibration is limited to pylon rock. Pylon rocking two to three cycles per second is inherent with the rotor, mast, and transmission system. To keep vibration
affect absorption or damping of existing
from reaching noticeable levels, transmission
vibrations and increase overall level felt by the pilot. A number of vibrations are present which are considered a normal characteristic of the machine. Two per revolution (2/rev) vibration is the most prominent of these, with 4/rev or 6/rev the next most prominent. There is always a small amount of high frequency present. Flight experience is necessary to Even levels. vibration normal learn
mount dampening is incorporated to absorb the rocking. Malfunctions in the dampening system will allow rocking to start and continue until it can be felt by the pilot. A quick check of the dampening system may be made by the pilot while in a hover. Moving cyclic foreand-aft at about one movement per second will start the pylon rocking. The length of time required for the rocking to die out after motion
experienced pilots sometimes make the mistake of concentration on feeling one specific vibration and conclude that the vibration level is higher than normal when
of the cyclic is stopped is indicative of the quality of the dampening. An abnormal continuation of rock during the normal flight is an indication something is wrong with the 18-00-00 Rev. 5
Page
5
BHT-212-MM transmission mounts or dampers. This may be due to wear, parts loosening up, breakage,
incorrect installations, or wrong type parts installed.
determine need for further action. Because of the idiosyncrasies of the individual blades, it
is occasionally adjustment
necessary
to attempt
procedure not normally utilized,
such as lateral procedures for a vertical, 18-5.
using roll when normally tab is used (and vice
Low frequency.
versa), or changing both tabs an equal
Low frequency vibrations, 1/rev and 2/rev, are caused by the rotor. 1/rev vibrations are of
amount.
two basic types; vertical or lateral. A 1/rev
Associated with the 1/rev vertical is the
vertical is caused by one blade developing more lift at a given point than the other blade develops at the same point. A lateral vibration is caused by a spanwise imbalance of the
intermittent 1/rev vertical. Essentially, this is a vibration initiated by a gust effect causing a momentary increase of lift in one blade giving a 1/rev vibration. This momentary increase is
rotor due to a weight difference between
normal but if picked up by the rotating
blades, alignment
collective controls and fed back to the rotor
of the CG of the blades
with respect to spanwise axis (which affects
causing
chordwise balance), or imbalance of hub or stabilizer bar. Rigidly controlled manufacturing processes and techniques eliminate all but minor differences between blades, resulting in blades which are virtually identical. The minor differences which remain
undesirable. Sometimes during steep turns, one blade will 'pop' out of track and cause a hard 1/rev vertical. This condition is usually caused by too much differential tab in the blades and can be corrected by rolling one blade at the grip and removing some of the
will affect flight but are compensated for by
tab (as much as can be done without
adjustments of trim tabs and pitch settings. Initially, the rotor is brought into ground track
disruption to the ride in normal flight). Should a rotor or rotor component be out of balance,
by normal tracking procedures, using the
a 1/rev vibration called a lateral will be
pitch change link (rolling the grip) to make a blade fly higher or lower to bring both blade tips into the same tip path plane. A track is taken using a higher operating rpm to determine if one blade is climbing (developing
present. This vibration is usually felt as a vertical due to the rolling motion it imparts to the helicopter, causing the pilots seats to bounce up and down. It can be noted that the seats bounce up and down out of phase; that
more lift) more than the other as its speed
is, the pilot goes up while the copilot goes
increases. This climbing tendency is overcome by adjusting the trim tabs after a
down. An unusually severe lateral can be felt as a definite sideward motion as well as a
flight check is made, then flying again to determine the effect. Because of the physical
differences in blades, it is sometimes necessary to roll a blade out of track slightly in order to get both blades developing the same amount of lift. Generally, verticals felt predominantly in low power descent at moderate airspeeds (60-70 knots) are caused by a basic difference in blade lift and can be
corrected by rolling the grip slightly out of track. Verticals felt mostly in forward flight which get worse as airspeed increases are usually due to one blade developing more lift with increased speed than the other (a climbing blade). This condition is corrected by adjustment of the trim tabs. Smoothing of 1/ rev verticals is essentially a trial and error process. A basic straight forward procedure is used but the outcome of any adjustment is
uncertain
and requires
18-00-00 Page
6
Rev. 5
flight-testing
to
several
cycles
of 1/rev,
it is
vertical motion. Laterals existing due to an imbalance in the rotor are of two types;
spanwise
and chordwise.
Spanwise
imbalance is caused simply by one blade and hub being heavier than the other (i.e., an imbalance along the rotor span). A chordwise imbalance means there is more weight toward the trailing edge of one blade than the other. Both types of imbalance can be caused by
the hub as well as the blades. Another occasional source of a lateral is the stabilizer bar. Improper balancing of the bar prior to installation is the main reason for this problem. Lateral vibrations are usually felt in a hover and in descending moderate airspeed turns and tend to disappear in forward flight. An out-of-ground effect hover is usually the best place to feel a lateral and reducing the rpm to 97% will often make the lateral more
prominent. The correction of 1/rev lateral
BHT-212-MM vibration begins by determining if one blade is
rotor itself can be caused by worn or loose
heavier than the other. This is done by wrapping one or two turns of 2.0 inches
parts in the rotor hub or looseness in the rotating controls. The correction of excessive
(50.8mm) masking tape (or equivalent weight
2/rev vibrations is primarily dependent upon
of another type) around one blade, a few
the mechanic. The pilot generally cannot
inches in from the tip. The helicopter is then
determine the exact cause and hence cannot
hovered, either in or out of ground effect, wherever the lateral was most evident, and
prescribe specific corrective procedures. Occasionally tab settings and sweep will
the effect of the tape noted. A worsening of the vibration means the tape was placed on the wrong blade. Once the correct blade is determined, further tape is added in amounts depending on the severity of the vibration until a final best balance using 1/2 wraps of
affect the overall 2/rev level. If no mechanical cause of excessive 2/rev can be found, an attempt to decrease the level by rotor adjustments may be made. It has been found that both blades may be swept in the same direction in small amounts and sometimes
tape is obtained. Should the lateral still be excessive or the tape not help on either
decrease 2/rev.
blade, a chordwise unbalance condition exists and it will be necessary to sweep a blade. One blade is arbitrarily picked and swept aft by shortening the drag link. One flat of turn (1/6 of full turn) is used to start with. The helicopter is then hovered and the effect
18-6.
Medium frequency vibrations at frequencies of 4/rev and 6/rev are another inherent vibration associated with most rotors. An increase in he level of these vibrations is caused by a
determined. Once it is ascertained that the
change in the capability of the fuselage to
correct blade is being swept, continued sweep adjustments in amounts based on the severity
absorb vibration, or a loose airframe component, such as the skids, vibrating at
of the vibration is used until the lateral is
that frequency. Changes in the fuselage
eliminated or further sweep fails to help. If still not satisfactory, it will be necessary to return to taping and adjust tape and sweep until the optimum combination is obtained. If it is still not possible to eliminate the lateral, a small amount of grip rolling should be attempted as
vibration absorption can be caused by such things as fuel level, external stores, structural damage, structural repairs, internal loading, or gross weight. Abnormal vibration levels of this range are nearly always caused by something loose; either a regular part of the helicopter or
Medium frequency.
in the 1/rev vertical procedure, being careful
part of the cargo or external stores. The
not to adversely affect forward flight. Should the lateral still be present, a small about of tab may be tried. If still not corrected, the hub
vibration is felt as a rattling in the fuselage. The most common cause is loose skids caused by worn, loose, or improper skid
and blades should be checked for grip spacing and if no problem found, then removed from the helicopter and the alignment checked and the stabilizer bar balanced.
retaining
straps. Loose skids can be
Two per rev (2/rev) vibrations are inherent
discovered by shaking the helicopter with cyclic and feeling if they vibrate or looking out the door at the skids while shaking the helicopter (excessive or severe shaking is undesirable and will make even tight skids vibrate). Many times skids will cause
with two bladed rotor systems and a low level of vibration is always present. A marked increase over the normal 2/rev level can be
considerable vibration during turns and maneuvers if they are extremely loose. Loose skids are not a serious condition but can
caused by two basic factors; a loss of
cause annoyance to flight crews and
designed dampening or absorption capability or an actual increase in the 2/rev vibration
passengers. Other sources of medium frequency vibrations are the elevator access
level of the rotor itself. The loss of dampening
doors, cargo hook, electronic gear, safety belt
can be caused
out the door, and engine/transmission
by such factors
as
deteriorated transmission mounts or lift link bushing, or an airframe component loosening up and vibrating in sympathy with the inherent 2/rev. An increase in the 2/rev level of the
cowling. Sometimes air loads will cause the small fire extinguisher doors and the step doors to vibrate. Occasionally, portions of the cabinet roof, side panels, or doors, will "oil" 18-00-00 Rev. 5
Page
7
BHT-212-MM
can rapidly in flight, giving the same sensation as a medium frequency vibration. 18-7.
High frequency.
High frequency vibrations can be caused by
anything in the helicopter that rotates or vibrates at a speed equal to or greater than that of the tail rotor. This includes many unusual situations such as hydraulic line
buzzing, or starter relay buzzing, to the most common and obvious causes; loose elevator linkage at swashplate horn, loose elevator, or tail rotor balance and track. Pilot experience can help greatly in troubleshooting the cause of a high frequency vibration, as a pilot who
cause and at least eliminating some possible causes. It should be recognized that
vibrations which are specifically being watched for, always appear more severe than when no particular attention is being directed to them. Many points on the airframe, such as surprisingly high the engine mounts, have a surprisingly high levelof high frequency vibration and it is easy to decide that the level is higher than normal
comparison between when actually it is not. A comparison between
the feel of a helicopter without excessive helicopter with the vibration
vibration and the helicopter with the vibration
is helpful in precluding erroneous conclusions 18-8.
TAIL ROTOR.
has experienced a vibration can often
recognize the cause the next time the same vibration is felt. Generally, determining the cause of a high frequency should begin with
Vibrations from the tail rotor can occur at the 1, 2, and 4/rev levels. In general, only the 1/ rev vibration can be corrected or reduced by
investigating tail rotor track (ground track using a rubber tipped stick with grease,
tracking and balancing the tail rotor.
lipstick, or some marking substance on the tip to mark the blades and determine if one is out
18-9.
of track).
vibration and and pulsation pulsation A high frequency frequency vibration
Should the rotor be properly in
track, balance should be checked by removing the tail rotor and hub assembly and checking on a balance stand. Should tail rotor balance check out also, an inspection of the complete driveshaft should be made. Physical damage like loss of balance tabs would be
OTHER VIBRATIONS
noise in cabin can be caused by the engine-
to-transmission driveshaft. This vibration can eliminated by proper balancing of the be eliminated by proper balancing of the engine-to-transmission driveshaft (paragraph engine-to-transmission driveshaft (paragraph 1-
evident. Observing the shaft with cover removed while rotor is turning, may show up a
18-10.
TROUBLESHOOTING.
bent shaft, faulty bearing, or some other troubles,
obvious malfunction. Attempting to locate the
Refer to Chapter 62 for potential
source of the vibration by feeling the fuselage
with the probable causes indicated and
in various places while ground running can sometimes be successful in localizing the
corrective action recommended which may occur in the main rotor assembly.
18-00-00 Page
8
Rev. 5
BHT-212-MM
ROTOR TRACKING AND BALANCING. 18-11.
MAIN ROTOR TRACKING.
Coat tracking tips of each blade with 1. grease pencil, using a different color on each tip.
18-12. MAIN ROTOR BLADE VIBRATION CHECK AND ADJUSTMENT. Refer to BHT-ALL-SPM for specification and source. MATERIALS REQUIRED
2.
Take a low-speed blade track (90% rpm)
Refer to BHT-ALL-SPM for specification and source
by following the steps in the tracking chart (figure 18-1).
NUMBER
NOMENCLATURE
C-405
Lockwire
Correct a low speed out-of-track
3.
condition by rolling down high blade as SPECIAL TOOLS REQUIRED
follows:
a. Loosen jamnuts on pitch change link of the high blade.
NUMBER
NOMENCLATURE
T101597
Bender
T101598
Gage
b. Turn pitch link barrel one flat at a time to lengthen pitch link.
NOTE
When troubleshooting for 1/rev
NOTE
vibrations, ensure helicopter does One flat rotation of barrel will result
not have a lateral 1/rev vibration
in approximately
before troubleshooting for a vertical
3/8 inch (9.525
mm) in blade track for all rpm.
c.
Tighten jamnuts and lockwire barrel to
nuts.
1/rev vibration. 1.
Fly helicopter through full airspeed range
and check for lateral vibration
(lateral
vibrations are usually more pronounced in hover). Verify adjustments have not changed autorotation rpm.
d. Recheck track with flag. Continue adjustments and checks until blades are in track.
2.
If lateral
procedures
vibration
is felt,
follow
charted in figure 18-2 (refer to
paragraph 18-13 for main rotor blade sweeping procedure).
4.
Take a high-speed track (100% rpm). NOTE
5. If blades are out of track at high speed, make no adjustments but record which blade is low (paragraph 18-12).
When lateral vibrations have been corrected by taping blades with 2.0 inches masking tape on blade tips, 18-00-00 Rev. 5
Page
9
BHT-212-MM example 2° down tab on one blade might, in some instances, have same effect as 6° up tab on opposite
tape is then removed and required weight added to blade bolt.
3.
Remove tape from blade, counting
blade.
number of wraps. 4. Remove cap from retaining bolt of taped blade.
5.
Add weight (lead (lead wool wool or or shot) shot) in in blade blade
18-13. 1813
BLADE SWEEPING. BLADE SWEEPING.
1. Loosen jamnuts on drag brace enough to turn barrel one flat AFT as shown by direction
bolt to compensate for weight of tape removed from blade tip, calculated as follows:
2.
adjustment, tighten jamnuts. Record After adjustment, tighten jamnuts. Record
adjustment. NOTE
3.
Make additional
as
required, but do not exceed two full turns of
blade tip equals approximately 3 ounces (0.227 kg) weight in blade
barrel.
bolt. 6.
adjustments,
One full wrap of masking tape on
NOTE
Install cap and secure with lockwire (C-
If maximum
adjustments
fail to
correct vibrations, rotor shall be removed from helicopter, placed on
7. Test fly helicopter. If no vibrations are felt, no further adjustment will be required. 8. If vertical vibrations are felt, designate high blade A and low blade B. Install a T101597 tab bender and a T101598 gage on
stand, and aligned using a scope. 4.
Torque jamnuts 275 to 325 ft.lbs. (373 to
blade and begin making blade adjustments
18-14.
according to figure 18-3, using blade
ADJUSTMENT.
designations
adjustments.
AUTOROTATION
RPM
to keep a running account of
See figure
18-4 for tool
application.
Refer to BHT-ALL-SPM for specification and source. MATERIALS REQUIRED Refer to BHT-ALL-SPM for specification and source.
TABS MAY BE BENT TO MAXIMUM
ANGLE OF 8° UP OR DOWN,
MAXIMUM
DIFFERENCE
C-405
BETWEEN BLADES OF 16° .
9. Test fly helicopter after each adjustment. Continue adjustments until vibration is worked out. Keep accurate record of all adjustments. NOTE
When bending tabs, experiment to see which tab has best effect with
least amount of bending. 18-00-00 Page
10
Rev. 5
For
Lockwire
Check rotor rpm in autorotation. Make straight ahead autorotative descent at constant 70 knots indicated airspeed (turns and changes of airspeed affect rotor rpm). Throttle should be at idle and collective full down. When in steady autorotative descent, note rotor rpm.
Refer to BHT-212-FM for allowable
autorotation rpm.
0im~~~~~~~~~~~~~~~~~~
Figure 18-1. Main rotor tracking
Rev. 5
BHT-212-MM
11
18-00-00 Page
-
Continueaddingtape.
Start
Satisfactory
(50.8 mm) tape to either RPM and check for lateral
blade tip.
motion of cockpit. in
adding tape.
other blade.
NOTES (D
A
Use amounts depending on
If grips have been rolled
severityof vibration.
excessively,
chordwise
Before adjusting for lateral, check
balance may have been affected. Realign blade that
need replacing.
flat increments.
Replace tape with equivalent lead
in blade bolt.
CAUTION EXCESSIVE SWEEP WILL CAUSE LATERAL VIBRATION. 212-M-18-2
*
Continue roll of high blade NOTES
down until air speed is 70
Tab low blade "B" up until
knots or above.
Roll high blade down to prevent auto-rotation becoming too low.
flight track is acquired.
NOTE Roll in 1/4 flat increments.
NOTE See table.
Check collective forces and makecorrections if necessary in conjunction with lateral vibration check.
Check for lateral vibration. 1:1 vertical with rotor in
Make corrections and resume
Roll high blade "A" down.
verticalprocedures.
good low track See lateral vibration chart.
0
Air speed at which 1:1 which 1:1
Amount of Roll or Tab or Tab
Below 40 Knots 40-60 Knots 60-70 Knots 70-80 Knots 80-90 Knots 90-100 Knots
1/2 Flat Roll 1/3 Flat Roll 1/4 Flat Roll 3/4 ° Tab 1/2 ° Tab 1/4° Tab
evident
TAB TABLE
rse
Check complete operation with smaller adjustments.
lade "B" down until air speed is 70 knots or above.
Tab up blade "A" until flight track is acquired. Satisfactory NOTE See table. 212-M-18-3
(D
BHT-212-MM
T1 101598 GAGE AT OUTBOARD END OF TRIM TAB
,
TIGHTENWINGNUTS BEFOREBENDINGTAB
HERE T101597 BENDER BOTTOMTAB IN SLOT
212-M-18-4
Figure 18-4. Trim tab bender and gage NOTE CAUTION
DO
NOT
ALLOW
ROTOR
exposed thread length of upper and lower fittings shall be equal within 2
TO
1/2 threads for pitch links without
EXCEED 104.5% RPM. 1. If rotor rpm is high, shorten both pitch change links equally. One turn of pitch link barrel changes rotor rpm approximately 2.5%.
thread engagement inspection holes. thread with links For pitch holes, inspection engagement exposed thread lengths shall be
If rotor rpm is low, lengthen both pitch 2. change links equally.
adequate thread engagement indicated at inspection hole.
3.
Tighten locknuts. Secure bottom locknut
to barrel, and top locknut to barrel and clevis with lockwire (C-405).
18-00-00 Page
14
Rev. 5
equal within 5 threads, provided
4.
Recheck rpm in flight
adjustment as necessary.
is
and repeat
BHT-212-MM
ROTOR TRACKING AND BALANCING SCIENTIFIC ATLANTA ROTOR ANALYSIS AND DIAGNOSTIC SYSTEM, MODEL AT (RADS AT).
18-15.
MAIN ROTOR TRACKING AND
BALANCING.
MATERIALSREQUIRED Refer to BHT-ALL-SPM for specification and source.
The following paragraphs provides the necessary information to track and balance the main rotor. The primary instrumentation for measuring rotor vibration is the Scientific
NUMBER
NOMENCLATURE
C-405
Lockwir
Atlanta
C-482
Duct tape
C-483
Reflective tape
Rotor Analysis
and Diagnostic
System, Model AT (RADS AT). The RADS AT automates the acquisitions of blade track and
vibration data as well as corrective actions
required to accomplish tracking and balancing. Also, the RADS AT automatically
18-17.
Installation - RADS AT
obtains blade sweep (lead-lag) information which helps to locate problem components in the hub and rotating control system.
1. Position and install 29328200 DAU in cabin aft of crew seats with connectors up.
1 8 -1 6. ROTOR V I B R A T I ON MEASUREMENT INSTRUMENTATION.
2. Using a 29329700 accelerometer bracket install one 991D accelerometer on front face of transmission island near the top with cable
connector to left (view A, figure 18-5). Connect end of 29105600 or 29105605
SPECIAL TOOLS REQUIRED NUMBER
P/N29333300
or
29313100 Scientific Atlanta San Diego,
NOMENCLATURE
accelerometer cable to accelerometer. Route cable to DAU so it does not foul controls. Connect to ACC CH1 port (figure 18-6).
Basic RADS AT kit
3.
with basic software 212 Version 4.20.
bracket, install one 991D accelerometer on the copilot side of the instrument panel face
CA 92123
P/N
29203300D
212/412
Optical
Scientific Atlanta
tracker bracket
P/N 29338500A Scientific Atlanta
212/412 Optical rotor adapter
P/N 29105600 29105605 Atlanta
or
Scientific
Accelerometer
tail
Connect end of 29105600 or 29105605 Route cable to DAU so it does not foul
controls. Connect to ACC CH2 port (figure 18-
cable
(additional)
4. Remove nuts and washers from top two bolts on left swashplate horn/boost cylinder
attachment (figure 18-7). Install 29312600 Accelerometer (2 total)
P/N
Accelerometer
Scientific Atlanta
adjacent to the pedestal with the cable connector down (View B, figure 18-5). accelerometer cable to vertical accelerometer.
P/N 991D Wilcox
29329700
Using a 29329700 accelerometer
brackets
Refer to BHT-ALL-SPM for specification and source.
magnetic sensor bracket to this location with
the hole for the sensor toward the mast.
Install new AN960JD416L washer and MS21042L4 nut on top two bolts and torque to 75 to 95 inch- lbs. (8.475 to 10.735 Nm). 5. Remove top jamnut from magnetic rpm sensor (27288400) and insert into magnetic 18-00-00 Rev. 5
Page
15
BHT-212-MM sensor support bracket. Reinstall outer jamnut
and loosely tighten so only one thread is showing beyond jamnut. Rotate rotor so magnetic interrupter is next to sensor. Adjust both jamnuts until gap between sensor and interrupter is 0.060 inch ± 0.010 (1.524 ± 0.254 mm). Tighten jamnuts while maintaining this spacing and secure with lockwire (C-405). Connect helicopter magnetic sensor cable to sensor and tighten to secure. 6. Move cyclic stick to the right rear position to fully extend left front control rod. Tiewrap magnetic rpm sensor cable to left control rod just below the rivets in the swaged end of tube with one inch of slack. Secure cable to
six inches minimum six leaving aa minimum airframe leaving airframe inches of of
Set angle of tracker (4) to 45 degrees
e.
as shown in figure 18-9. Tighten bolts to secure tracker in position. CAUTION
DO NOT BLOCK STATIC PORTS
ON SIDE
OF NOSE WHEN
ROUTING CABLE. 9. Connect tracker cable (6) to tracker (4) and route through lower front edge of copilot door. Secure cable to nose using tape (C-
482). Route cable in cabin to avoid flight
slack between airframe and control tube to allow for movement of controls and pylon in flight. Route cable under cowling and into
controls and connect to Tracker #1 on DAU
cabin through left cargo door and secure
communications cable 29325601.
cable. Connect opposite end of cable to port TACHO TACHO #1 #1 on on DAU. DAU. Connect 29104700 28 VDC power cable 7. to 28 VDC port on copilot side of pedestal. Connect opposite end of cable to 28 VDC connector on the DAU 8.
Install day-night optical tracker (4, figure
10
Connect CADU 29314101 to DAU using
11. Install for tapenight (C-483) on trailing of each blade tracking (figure edge 18-10). Paint leading edge of each blade black for daylight tracking. 12.
The RADS is now installed and ready to
smooth the rotor system. When correctly installed, RADS should be configured as
18-8) as follows: a. Remove screws (1) left side of upper nose panel.
18-18.
Flight tests to smooth rotor.
Table 18-1 shows tests conditions used by b. Position tracker bracket (8) on left nose panel and secure using bolts (7).
various flight plans to smooth the rotor. It is recommended all flight tests be conducted at
c. Torque bolts (7) 15 to 20 inch-lbs. (1.69 to 2.69 Nm).
configuration for which RADS diagnostics have been optimized. The recommended
Install the day-night optical tracker (4) d. on bracket (8) using bolts (9), washers (3),
and nut (5). Tighten upper bolt enough to allow tracker to be moved by hand.
NOTE
a light gross weight as this is the
configuration is two/three crew and 500 to 1500 lbs. of fuel. Two flight plans are used to smooth the rotor system. These are: INITIAL: The purpose of this mode is to track rotor on ground and in hover and to balance rotor while on the ground. This mode is used
to set up rotors with one or more major component changes prior to flight (i.e. blade,
Use an inclinometer to verify the
hub, pitch link, etc.). The purpose of this
angle of tracker when first installed on a new mount. Scribe mark angle on mount so subsequent
mode is to track rotor at both low (62 percent) and high (100 percent) rotor rpm to properly set up the pitch links and trim tabs for flight
installations will not require an inclinometer for alignment.
and to balance rotor in hover (or on the ground at 100 percent rpm if the hover
18-00-00 Page 16
Rev. 5
BHT-212-MM
LATERAL ACCELEROMETER LOCATED ON FRONT FACE OF TRANSMISSION ISLAND AS SHOWN WITH CONNECTOR TO THE LEFT
FRONT FACE OF TRANSMISSION ISLAND (LOOKING AFT) VIEW A. LOCATION OF LATERAL ACCELEROMETER
VERTICAL ACCELEROMETER LOCATED ON FRONT FACE OF INSTRUMENT PANEL WITH CONNECTOR DOWN
VIEW B. LOCATION OF LATERAL ACCELEROMETER
212-M-18-5
Figure 18-5. Accelerometer locations
Rev. 5
18-00-00 Page 17
BHT-212-MM LATERAL ACCELEROMETER
MAGNETIC RPM SENSOR
ACC #1 VERTICAL ACCELEROMETER
TACHO #1
PEDESTAL 28VDC
ACC #2
CADU PORT TRACKER #1
OPTICAL TRACKER
CADU
212-M-18-6
Figure 18-6. Main rotor--
18-00-00 Page
18
Rev. 5
proper RADS AT installation
BHT-212-MM
LEFT CYCLIC SWASHPLATE HORN/BOOST CYLINDER ATTACHMENT
MAGNETIC RPM SENSOR BRACKET LOCATION TORQUE 75 to 95 IN-LBS (8.475 to 10.735 Nm)
LOCATION OF MAGNETIC RPM SENSOR
DRIVE LINK
ROTATING SWASHPLATE
TARGET BLADE MAGNETIC RPM SENSOR MAGNETIC SENSOR BRACKET
DRIVE LINK
REMOVE NUTS AND WASHERS FROM THESE TWO STUDS TO INSTALL MAGNETIC RPM SENSOR BRACKET TORQUE 75 TO 95 IN-LBS (8.475 TO 10.735 Nm)
MAGNETIC RPM SENSOR INSTALLATION
212-M-18-7
Figure 18-7. Magnetic pickup and interrupter
Rev. 5
18-00-00 Page 19
BHT-212-MM
1.
Bolt
2. Door 3. Washer or shim
4. Optical tracker 6. Tracker cable SEE DETAILB SEE DETAIL SEEDETAILA
Tracker bracket bracket 8. Tracker 9.
Bolt
15TO 20 IN-LBS. (1.69 TO 2.69 Nm)
ROUTE TRACKER CABLE AS SHOW SO THAT IT ENTERS COCKPIT AT LOWER FORWARD CORNER OF COPILOT DOOR. SECURE WITH DUCT TAPE.
DO NOT LET TRACKER CABLE OR TAPE COVER AIRSPEED STATIC PORTS.
Figure 18-8. Passive optical tracker location and cable routing
18-00-00 Page 20
Rev. 5
212-M-18-8 212-M-18-8
BHT-212-MM
TRACKERANGLE 42
FLOOROF AIRCRAFT MEASURED AT SEAT RAIL DAYLIGHTTRACKER ANGLE
212-M-18-9
Figure 18-9. Optical tracker angle
.
information is missing). By using the initial mode, excessive 1/rev vibration in forward
select AIRCRAFT TYPE and press DO. Use arrow keys to highlight 212 and press DO.
flight can be avoided during the first flight after maintenance. Once the helicopter has
been flown, the initial test does not need to be conducted again until the next major rotor
maintenance. For procedures to perform INITIAL mode test refer to step 1. FLIGHT:
main rotor 1/rev. It is also used as a follow on to the INITIAL test when that test has been successfully accomplished after replacement
main rotor components.
procedures to perform FLIGHT prefer to step 2.romFH
For
mode test md et
Smooth rotor with RADS AT (INITIAL 1. mode) as follows:
a.
With helicopter type select, press DO
to selected
or define TAIL NUMBER of
helicopter (BHT prefers operator to use S/N
and not registration number). When TAIL NUMBER has been highlighted or defined, press DO to select.
The purpose of this mode is for
periodic/routine smoothing with respect to
of major
c.
Ensure system is installed properly
d.
With helicopter te
and ail number
defied, select INITIAL as the FLIGHT PLAN and press DO.
e.
Once the CADU is properly configured
for the initial mode, the CADU screen should look similar to example in figure 18-11. With CADU properly configured, press F1 to initiate MEASUREMENT mode of RADS. MEASUREMENT mode of RADS.
f. Operate helicopter with one engine and stabilize main rotor rpm at approximately 62
percent
NR. Center cyclic
and ensure
(paragraph 18-17).
collective is all the way down.
b. Turn on CADU to review main screen. Press QUIT until the main screen has been cleared of previous entries. Use arrow keys to
On CADU highlight IDLE and press g. checks are DO to select. If all internal successful the test condition title will appear 18-00-00 Rev. 5
Page
21
BHT-212-MM at the bottom of screen and the system will be armed to collect data. Press DO again to begin data collection. Once all data has been obtained, The CADU will indicate to proceed to next test condition.
If any limits are exceeded, rotor adjustments should be made and initial mode repeated.
NOTE
k. With limits page displayed press DO to display recommended rotor adjustments.
Upon completion of obtaining data
NOTE
l.
Using arrow keys, scroll through
do not push QUIT until the list of test conditions appears or an error
recommended adjustments. Record adjustments on form shown in figure 18-12.
previous test condition will be erased. If any warnings appear, attempt to retake data at the test condition. If warning repeats, record error code and shut down helicopter. Perform corrective action. Refer to table 18-3 for corrective action.
m. Press DO to review predicted results and DO again to view DIAGNOSTICS menu. If all adjustments have been recorded then select MAIN MENU and press DO to return to main menu.
message appears as all data from
NOTE
h.
Start second engine once data has
been collected at IDLE. On CADU highlight FPG100 and HOVER and press DO to arm. Press DO again to begin data collection when
To view predictions on 6.01 systems select VIEW PREDICTIONS from main menu.
helicopter has been stabilized at desired condition.
i. If helicopter is vibrating excessively on the ground it is acceptable to skip HOVER test condition and: (1) mode.
Press QUIT to exit measurement
When in EDIT ADJUSTABLES, one and only one each span balance and chord balance adjustments must be turned on at al times. n. Make adjustments in accordance with paragraphs 18-23 through 18-26. NOTE
(2) Using arrow keys select SAVE and exit and press DO to save all data obtained.
The word limit does not mean an actual limit for track or vibration that cannot be exceeded, but only refers to terminology used in RADS AT to guide tracking and balancing of components.
(3) Select DIAGNOSTICS from menu and press DO. If you have returned to main menu press F3 to enter DIAGNOSTICS menu. (4)
Proceed to step K.
j. Upon completion of collecting data at both test conditions land helicopter, but do
not shutdown. Select DIAGNOSTICSfrom menu. If limits are exceeded these will be shown on screen. If no limits are exceeded then helicopter is ready to be smoothed in forward flight. Press QUIT to return to main menu and bypass the recommended rotor adjustments. If any limits are exceeded proceed to next step. 18-00-00 Page 22
Rev. 5
o.
Repeat steps a. through n. until all
initial limits have been met. Once all limits have been met, proceed to the FLIGHT test mode (step 2). No further initial runs are
required until next major rotor system maintenance. 2. Smooth rotor with RADS AT (FLIGHT mode) as follows: a. Ensure system is installed (paragraph 18-17).
BHT-212-MM OUTBOARD
36 INCHES
PAINT INSTALLATION FOR DAY TRACKING
OUTBOARD
36 INCHES
REFLECTIVE TAPE FOR NIGHT TRACKING 212-M-18-10
Figure 18-10. Location of paint and tape for tracking
Rev. 5
18-00-00 Page 23
BHT-212-MM
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 3.10AP35D 18-APR-94 12:29:08 Aircraft Type Tail Number
212 4.1 35###
Flight Plan
INITIAL
Flight I.D.
MEASURE
DISPLAY
DIAGS
MANAGER
INITIALMODE
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 18-APR-94 Aircraft Type Tail Number
212 4.1 35###
Flight Plan Flight I.D.
FLIGHT
MEASURE
DISPLAY
3.1 OAP35D 12:29:08
DIAGS
MANAGER
FLIGHT MODE
212-M-18-11
Figure 18-11. Main rotor smoothing CADU screen
18-00-00 Page
24
Rev. 5
BHT-212-MM SHIP S/N =
TARGET =
RADS AT FLIGHT I.D.
BLADE I.D.
SPAN BALANCE
BLANK =
SWEEP
PITCH LINK
OUTBOARD TAB
SPAN BALANCE
SWEEP
PITCH LINK
OUTBOARD TAB
SPAN BALANCE
SWEEP
PITCH LINK
OUTBOARD TAB
DATE =
BLANK TIME =
TARGET NOTES ON PREVIOUS FLIGHT: RADS AT FLIGHT I.D.
BLADE I.D.
DATE =
BLANK TIME =
TARGET NOTES ON PREVIOUS FLIGHT:
RADS AT FLIGHT I.D.
BLADE I.D.
DATE = BLANK
TIME = TARGET NOTES ON PREVIOUS FLIGHT: RADS AT
BLADE
SPAN
PITCH
OUTBOARD
FLIGHT I.D. DATE =
I.D.
BALANCE
SWEEP
LINK
TAB
SPAN BALANCE
SWEEP
PITCH LINK
OUTBOARD TAB
BLANK TIME =
TARGET NOTES ON PREVIOUS FLIGHT: FINAL SETTINGS
RADS AT FLIGHT I.D.
BLADE I.D.
DATE =
BLANK TIME =
TARGET 212-M-18-12
Figure 18-12. Model 212 main rotor adjustment log
Rev. 5
18-00-00 Page 25
BHT-212-MM b. Turn on CADU to view main screen. Press QUIT until the main screen has been cleared of previous entries. Use arrow keys to select AIRCRAFT TYPE and press DO. Use arrows to highlight 212 and press DO.
e. Once the CADU is properly configured for the initial mode, the CADU screen should look similar to With to example example in in figure figure 18-11. 18-11. With look similar CADU properly configured, press F1 to initiate MEASUREMENT mode of RADS. NOTE
c. With helicopter type selected, press DO to select or define TAIL NUMBER of helicopter and not NUMBER press DO
(BHTI prefers operator to use S/N registration number). When TAIL has been highlighted or defined, to select.
When continuing
from an INITIAL
test you must repeat the IDLE, FPG100 and HOVER test.
d. With helicopter type and tail number defined, select INITIAL as the FLIGHT PLAN and press DO.
Table 18-1. Test conditions-
Main rotor
INITIAL
FLIGHT/ 2/R-CHK
TEST DESCRIPTION
LATERAL LIMIT
VERTICAL LIMIT
IDLE
IDLE
Flat Pitch at 62% Rotor RPM
FPG100
FPG100
Flat Pitch at 100% Rotor RPM
0.5 IPS
HOVER
HOVER
Hover into wind
0.1 IPS
60K
Level Flight at 60 knots
0.20 IPS
110K
Level Flight at 110 Knots
0.20 IPS
L/DOWN
70 Knot Letdown at 1000 Ft/Mn
0.20 IPS
NOTE
The limits in the above table are not actual airframe or ride quality limits, but are
used to guide the RADS diagnostics program. Actual recommended vibration criteria can be found in table 18-2.
18-00-00 Page
26
Rev. 5
BHT-212-MM Table 18-2. Vibration criteria -
Main rotor
SOURCE
IDENTIFICATION
LEVEL-
IPS
RECOMMENDED ACTION
MAIN ROTOR 1/REV
HOVER LATERAL
LEVEL -
0.2
No action recommended
LEVEL -
0.2
Balance rotor when practical
60 to 110 KNOT VERTICAL
f. Operate helicopter on both engines and obtain data at each test condition shown on screen using basic procedures of steps f. and g. of INITIAL mode testing. When obtaining data in flight it is not necessary to obtain data at high speed test conditions if the 1/rev becomes higher than is comfortable. When skipping test conditions or acquiring data out of sequence the arrow keys can be used to select the desired conditions.
LEVELS -
0.2
No action recommended
0.2 -
LEVELS 0.5
Reduce at customer option no action required
0.5 -
LEVELS 1.0
Reduce as soon as practical
1.0 -
LEVELS
Remove aircraft from service; reduce as soon as possible
g. When data to be obtained have been collected, land and shutdown helicopter. If all data have been collected the program will automatically display menu options. If all test
conditions have not been obtained, press QUIT to exit MEASUREMENT MODE. Use arrow keys to select SAVE and EXIT. Press DO to store all data.
h. Using arrow keys highlight DIAGNOSTICS and press DO to select. If you have returned to main menu, press F3 to enter DIAGNOSTICS MENU.
NOTE
The RADS AT needs only the on forward flight condition to begin to analyze the adjustments required to
i. Compare data obtained to limits listed in table 18-3. If no limits are exceeded press QUIT to exit program.
smooth the rotor. It is important
however, as 1/rev levels are reduced, to obtain data at all
NOTE
displayed test conditions to ensure
Using arrow keys scroll through
that optimum rotor 1/rev levels are achieved throughout the flight envelope of helicopter.
recommended adjustments. Record adjustments on form shown in figure 18-12.
Never store data from one test condition under another label or diagnosis will not function properly.
j.
Press DO to review predicted results
and DO again to view DIAGNOSTICS menu. If all adjustments have been recorded then 18-00-00 Rev. 5
Page
27
BHT-212-MM NOTE
select MAIN MENU and press DO to return to main menu.
When in EDIT ADJUSTABLES, one and only one each span balance and chord balance adjustments must be turned on at all times.
NOTE To view predictions on 6.01 systems select VIEW PREDICTIONS from
main menu. adjustments
If three
If any 1/rev levels are above limits it
is up to operator to determine if
or more
are recommended
levels require further improvement.
or
the recommended adjustments
o. With limits page displayed press DO to display recommended rotor adjustments.
include bending outboard tab in direction opposite indicated pitch link adjustment, acceptable ride may be obtained with fewer adjustment.
Using
k.
arrow
keys select
p.
EDIT
best adjustments,
To calculate
paragraphs 18-23 through 18-26. Repeat steps e. through n. until acceptable ride is obtained.
DEFAULTS and press DO. I.
Make adjustments in accordance with
type
q.
Remove RADS AT in accordance with
number one (1) and press DO. Note adjustments and view predicted results. If predicted results are satisfactory record
paragraph 18-22.
adjustments on figure 18-12.
(OPTIONAL).
Make adjustments in accordance with m. paragraphs 18-23 through 18-26 and proceed to step n.
18-20. AT.
If predicted results are not acceptable n. repeat EDIT DEFAULTS and select 2, 3, and then 4, if necessary, until predicted results are acceptable. Record adjustments on form shown on figure 18-12. Make adjustments in accordance with accordance with paragraphs paragraphs 18-23 18-23 through through
18-19.
MAIN ROTOR 2/REV
CHECK
Installation for 2/rev check RADS
Install and secure 29328200 DAU in 1. cabin aft of crew seats with connectors up. Using a 29329700 accelerometer bracket 2. install one 991D accelerometer on the pilots outboard seat rail, using forward stop bolt to secure, with cable connector up. Connect end
of 29105600 or 29105605
accelerometer
NOTE
cable to accelerometer. Route cable to DAU so it does not foul controls. Connect to ACC CH3 port (figure 18-13).
For diagnostics to work properly the HOVER and at least one forward speed must be obtained. If a limited number of tests points has been must be adjustments obtained, edited using EDIT ADJUSTABLES option of DIAGNOSTICS menu. The following edit is required:
accelerometer Using a 29329700 3. on accelerometer 991D one bracket, install forward using rail, seat the copilot outboard stop bolt to secure, with the cable connector up. Connect end of 29105600 or 29105605 accelerometer cable to vertical accelerometer. Route cable to DAU so it does not foul controls. Connect to ACC CH4 port (figure 1813).
No forward airspeed: Turn off (use F1 to select N) both pitch links and trim tab. If this is not done these adjustments will be used to track the rotor on the ground. 18-00-00 Page
28
Rev. 5
Remove nuts and washers from top two 4. bolts on left swashplate horn/boost cylinder attachment (figure 18-7). Install 29312600 magnetic sensor bracket to this location with
BHT-212-MM
the hole for the sensor toward the mast.
6.
Install new AN960JD416L washer and MS21042L4 nut on top two bolts and torque to 75 to 95 inch-lbs. (8.475 to 10.735 Nm).
to fully extend left front control rod. Tiewrap magnetic rpm sensor cable to left hand control rod just below the rivets in the swaged end of tube with one inch of slack. Secure
Remove top jamnut from 27288400
cable to airframe leaving a minimum six
magnetic rpm sensor and insert into magnetic sensor support bracket. Reinstall outer jamnut and loosely tighten so only one thread is showing beyond jamnut. Rotate rotor so magnetic interrupter is next to sensor. Adjust both jamnuts until gap between sensor and interrupter is 0.060 inch ± 0.010 (1.524 ± 0.254 mm). Tighten jamnuts while maintaining this spacing and secure with lockwire (C-405). Connect helicopter magnetic sensor cable to sensor and tighten to secure.
inches of slack between airframe and control tube to allow for movement of controls and pylon in flight. Route cable under cowling and into cabin through left cargo door and secure cable. Connect opposite end of cable to port TACHO #1 on DAU.
5.
Move cyclic stick to the right rear position
7. Connect 29104700 28 VDC power cable to 28 VDC port on copilots side of pedestal. Connect opposite end of cable to 28 VDC connector on the DAU.
Table 18-3. Troubleshooting INDICATION OF TROUBLE
PROBABLE CAUSE
CORRECTIVE ACTION
Adjustments do not reduce 1/rev
Improper accelerometer installation.
Refer to appropriate section in this manual for proper installation.
Data is not stored when flight condition is completed
Operator pressing 'QUIT' before data is stored.
Do not press 'QUIT' unless it is to clear a warning or leave the list of test conditions.
Accelerometer saturation
Soft accelerometer bracket.
Install thicker bracket.
Damaged accelerometer cable.
Replace cable.
Failed accelerometer.
Replace accelerometer.
Magnetic sensor gap too wide.
Adjust gap minimum 0.025 inch (0.635 mm), maximum 0.07 inch (1.79 mm).
Damaged magnetic sensor cable.
Replace cable.
Wrong tracker angle.
Set tracker to 45 degrees.
Bright blade leading edge.
Paint leading edge blade color.
Corruption by sun.
Install sunshield.
Photocell tape not in correct position.
Lengthen tape, make sure red light is on the photocell when rotor is flapped or
Tacho failure
Track failures or obviously bad track data
Tacho out-of-bounds when checking tail rotor or driveshaft
18-00-00 Rev. 5
Page
29
BHT-212-MM
Table 18-3. Troubleshooting (Cont)
INDICATION OF TROUBLE
PROBABLE CAUSE
CORRECTIVE ACTION reflector is under photocell on the driveshaft.
Corruption by sun.
Orient aircraft so photocell is not pointing at the sun for the tail rotor or so driveshaft is in shadow.
CADU will not communicate with DAU
18-21. 1.
Shorted tracker cable.
2/Rev check - RADS AT.
Smooth rotor with RADS as follows: a.
Ensure system
is installed
select HELICOPTER TYPE and press DO.
c.
h.
If levels are found to be higher than
normal refer to table 18-3 for corrective
b. Turn on CADU to view main screen. Press QUIT until the main screen has been Use arrow keys to highlight DO.
g. When all data has been obtained, land helicopter. Select MAIN MENU and press F2 to display. Select SINGLE FLIGHT and record data, time, and date on form shown in figure 18-15.
properly
(paragraph 18-17).
Remove tracker cable. If problem is solved replace or repair tracker cable.
action.
i.
Make adjustment
in accordance
with
table 18-3 until acceptable ride is obtained.
212 and press Remove RADS AT in accordance with j. paragraph 18-22.
With helicopter type selected, press
DO to selected or define TAIL NUMBER of helicopter (BHT prefers operator to use S/N and not registration number). When TAIL NUMBER has been highlighted or defined, press DO to select.
1. Disconnect 28 VDC power cord from 28 VDC port on copilot side of pedestal and DAU.
d. With helicopter type and tail number defined, select 2/R-CHK as the FLIGHT PLAN and press DO.
2. Disconnect 29325601 communication cable from CDAU and DAU.
e. Once the CADU is properly configured for the initial mode, the CADU screen should look similar to example in figure 18-14. With CADU properly configured, press F1 to initiate MEASUREMENT mode of RADS. f.
Fly helicopter and obtain data in the 2/
18-22.
Removal - RADS AT.
Disconnect tracker cable from tracker 3. and remove cable. 4. Remove day/night optical tracker bracket. 5.
and
Remove magnetic sensor and bracket
R-CHK mode. Refer to table 18-1 for test
from left side of swashplate horn/boost
conditions.
cylinder. Install nuts and washer removed and
18-00-00 Page 30
Rev. 5
BHT-212-MM
ACCELEROMETER COPILOT FORWARD SEAT RAIL
ACC #3
ACCELEROMETER MAGNETIC RPM SENSOR
PILOT OUTBOARD SEAT RAIL
ACC #4
TACHO #1
PEDESTAL
28VDC CADU DAU
PORT
CADU
212-M-18-13
Figure 18-13. RADS AT proper configuration
(2/R-CHK)
18-00-00 Rev. 5
Page
31
BHT-212-MM
SCIENTIFIC ATLANTA RADS AT VERSION 18-APR-94 Aircraft Type
212 4.1
Tail Number Flight Plan
35### 2/R-CHK
STEWART HUGHES 3.1 OAP35D 12:29:08
Flight I.D.
MEASURE
DISPLAY
DIAGS
MANAGER 212-M-18-14
Figure 18-14. Main rotor smoothing CADU screen (2/R-CHK)
torque to 75 to 95 inch-lbs. (8.475 to 10.735 Nm).
18-23. SPAN BALANCE ADJUSTMENT RADS AT.
-
and
The RADS AT specifies the amount of span balance adjustment to be made in grams with
side of
a positive (+) adjustment meaning to add
instrument instrument panel panel face face adjacent adjacent to to pedestal. pedestal.
weight to the designated andweight a negative from remove meaning toblade (-) adjustment blade. If the RADS AT the designated specifies to remove weight from the blank blade and that blade does not have weight, then add the weight to the target blade. The
6.
Remove
29329700
991D
accelerometer
bracket from copilot
Install new nut and washer and torque 50 to 70 inch-lbs. (5.65 to 7.91 Nm).
7.
Remove 991D accelerometer
and
29329700 accelerometer bracket from front face of transmission island.
8.
Remove
29105600
or 29105605
accelerometer cables.
effect will be identical.
adjustment Review span balance 1. recorded on the adjustment log to determine the adjustment to be made. Refer to rotor
adjustment log to verify blade identification to ensure correct blade is adjusted. The span balance location is inside blade bolts (figure 18-16).
9. Remove 29328200 DAU from cabin aft of crew seats.
NOTE
10. Store the final flight in the CADU or on a computer for future reference.
Lead shot (0.44 caliber) weighs nine grams per ball. If none is available use electronic scale to determine
18-00-00 Page
32
Rev. 5
BHT-212-MM BLANK =
TARGET =
SHIP S/N = RADS AT FLIGHT I.D.
LOCATION
HOVER 2/REV
60K 2/REV
110K 2/REV
HOVER 2/REV
60K 2/REV
110K 2/REV
HOVER 2/REV
60K 2/REV
110K 2/REV
DATE PILOT TIME =
COPILOT NOTES ON PREVIOUS RUN:
RADSAT FLIGHT I.D.
LOCATION
DATE =
PILOT TIME =
COPILOT NOTES ON PREVIOUS RUN:
RADS AT FLIGHT I.D. DATE=
LOCATION PILOT
TIME =
COPILOT NOTES ON PREVIOUS RUN:
RADS AT
HOVER
60K
110K
FLIGHT I.D.
2/REV
2/REV
2/REV
LOCATION
DATE =
PILOT TIME = COPILOT NOTES ON PREVIOUS RUN:
212-M-18-15
Figure 18-15. Model 212 main rotor adjustment log (2/R-CHK)
Rev. 5
18-00-00 Page 33
BHT-212-MM
SPAN BALANCE LOCATED IN BOLT
MAIN ROTOR PITCH LINK TORQUE 650 to 800 IN-LBS (73.45 to 90.40 Nm)
DRAG BRACE TORQUE 275 TO 325 FT-LBS (372.845 TO 440.635 Nm) TRIM TAB
212-M-18-16
Figure 18-16. Main rotor adjustments
18-00-00 Page
34
Rev. 5
BHT-212-MM
amount of alternate weight to be
present in the opposite blade bolts then
used.
remove weight from that blade prior to adding to original blade.
2. Once blade to be adjusted has been identified remove safety wire from plug of selected blade bolt and remove plug.
3.
4. Install all plugs removed and safety with lockwire.
Add weight to blade bolt (0.44 caliber
lead shot recommended). If weight is already Table 18-4. Accelerometer location, channel and installations LOCATION
ORIENTATION
INSTALLATION
1
Aft cabin bulkhead
Lateral, connector right
Section 3.3 (b)
2
Pilot seat rail
Vertical, connector up
Section 5.2 (b)
3
Combining gearbox lateral
Lateral connector to right
Section 6.2 (c)
4
90 degree gearbox
Vertical with connector up
Section 4.3.1(d)
CHANNEL I.D.
Table 18-5. Test conditions (VIBCHK) TEST I.D.
Main rotor
CHANNEL I.D.
FREQUENCY RANGE
ACC #1
250 HZ
Ground run at 100% rpm with data from aft cabin bulkhead lateral
GR-CH3
ACC #3
250HZ
Ground run at 100% rpm with data from engine combining gearbox lateral
GR-CH4
ACC #4
250 HZ
Ground run at 100% rpm with data from tail rotor gearbox vertical
FL-CH1
ACC #1
250 HZ
Level flight at 110 knots with data from aft cabin bulkhead lateral
FL-CH2
ACC #2
250 HZ
GR-CH1
TEST DESCRIPTION
GR-CH2 ACC #2 250 HZ Ground run at
100% rpm with data from pilot seat vertical
Level flight at 110 knots with data from pilot
seat vertical 18-00-00 Rev. 5
Page
35
BHT-212-MM Table 18-5. Test conditions (VIBCHK) -
Main rotor (Cont)
TEST
CHANNEL
FREQUENCY
I.D.
I.D.
RANGE
FL-CH3
ACC #3
250 HZ
Level flight at 110 knots with data from engine combining gearbox lateral
FL-CH4
ACC #4
250 HZ
Level flight at 110 knots with data from tail rotor gearbox vertical
1KHZ-3
ACC #3
1000 HZ
Level flight at 110 knots with data from engine combining gearbox lateral
1KHZ-4
ACC #4
1000 HZ
Level flight at 110 knots with data from tail rotor gearbox vertical
18-24.
SWEEP ADJUSTMENT - RADS AT.
TEST DESCRIPTION
4. Rotate drag brace barrel the number of flats required for adjustment (down sweeps blade aft and up sweeps blade forward.
CAUTION
AT NO TIME SHOULD THE BLADE
5. Holding drag brace barrel torque inboard and outboard jamnuts 275 to 325 Ft. Ibs. (372.845 to 440.635 Nm) and safety with
BE SWEPT FORWARD OF THE
lockwire.
ALIGNED
POSITION.
IT IS
ACCEPTABLE TO REMOVE AFT SWEEP BY SWEEPING FORWARD.
18-25. AT.
The RADS AT uses sweep as the primary adjustment for chordwise balance. The RADS AT specifies sweep in number of flats of adjustment of the outboard drag brace nut. A positive (+) adjustment means to sweep the blade aft and a negative (-) adjustment means to sweep blade forward. Once rotor has been aligned prior to installation, a grease pencil mark should be made on each outboard drag brace nut and clevis to indicate the aligned position. 1.
Review sweep adjustment recorded on
the adjustment
log to determine
PITCH LINK ADJUSTMENT - RADS
The RADS AT specifies the amount of pitch link adjustment to be made in the number of flats of the pitch link barrel with a positive (+) meaning increase pitch and negative (-) meaning decrease pitch. 1. Review sweep adjustment recorded on the adjustment log to determine the magnitude and direction of the adjustment to be made. Refer to rotor adjustment log verify blade identification to ensure correct blade is adjusted.
the
magnitude and direction of the adjustment to be made. Refer to rotor adjustment log verify blade identification to ensure correct blade is adjusted.
2. identified remoe lock and lower jamnuts of pitch link while holding barrel with a wrench.
2. Once blade to be adjusted has been identified remove lockwire from the two drag brace jamnuts.
Mark pitch link barrel and lower clevis 3. with grease pencil to show original alignment.
3.
4.
Loosen inboard and outboard drag brace
jamnuts. 18-00-00 Page 36
Using
wrench,
turn
barrel
number of flats for adjustment. Rev. 5
required
BHT-212-MM 3.
NOTE
Using a piece of lockwire verify
touching angle indicator on bender.
If adequate thread engagement. threads are not felt with lockwire, rig pitch links prior to further helicopter operation. 5. Equalize clearance on the inside of lower pitch link clevis. Holding barrel torque 650 to 800 inch-lbs (73.45 to 90.40 Nm) and safety with lockwire.
OUTBOARD
18-26.
TRIM TABS
ADJUSTMENT - RADS AT.
NOMENCLATURE
T101654-101
Trim tab bender
T101656-145
Trim tab gage
4. Bend tab in required direction until tab is at rest (no load on bender) approximately two degrees beyond desired final tab angle. Bend tab back until desired angle is reached. This overbending will minimize any tendency of the tab to creep over time. Remove tab gauge and tab bender from 5. blade.
18-27.
The following paragraphs contain procedures to provide the operator the ability to monitor the general vibration levels of the helicopter over time. This is accomplished by using the
general spectrum analysis capability of the RADS AT. The 212 software contains a flight plan VIBCHK with 250 Hz spectrums for use
with four accelerometers the amount of The RADS AT specifies outboard trim tab adjustment to be made in
number of degrees with positive adjustment
meaning
CHECK
GENERAL VIBRATION
(OPTIONAL) - RADS AT.
SPECIAL TOOLS REQUIRED NUMBER
Install T101598 tab gauge to blades with
correct scale adjacent to trim tab. Square gauge to chord line of blade with scale
(+)
bend tab up and
negative (-) meaning bend tab down.
and 100 Hz
spectrums for use with two accelerometers.
18-28. Installation (VIBCHK) - RADS AT. Install and secure 29328200 DAU in
Adjustment of 0.25 degrees is provided to
1.
allow the biasing of 0.50 degree moves to the light (undershoot) or heavy (overshoot) side.
cabin aft of crew with connectors up.
NOTE It is good practice to have the total amount of bend in each of the blade tabs equal.
1.
Review outboard tab adjustment
recorded on the adjustment log to determine the magnitude and direction of the adjustment to be made. Refer to rotor adjustment log
2.
Install four accelerometers. Refer to table
18-4 for location
and installation
of
accelerometers. 3. Secure tail rotor cable down fin and under tailboom so it cannot foul elevator or rotating components. Ensure cables are clear of engine exhaust. to DAU accelerometers 4. Connect channels (table 18-4) using 29105600 or 29105605 accelerometer cable.
verify blade identification to ensure correct blade is adjusted.
2.
Loosen wing nuts and install trim tab
bender T101597 on trim tab to be adjusted. Position bender so that there is approximately 1/8-inch gap between bender and trailing edge of blade. Tighten wing nuts to secure bender to blade.
5. Connect 29325601 communication cable to CADU port on DAU and opposite end to
the CADU. Connect 29104700 28 VDC power cable 6. to 28 VDC port on copilot side of pedestal. Connect opposite end of cable to 28 VDC connect on DAU. Rev. 5
18-00-00 Page 37
BHT-212-MM 7. The RADS AT should now be installed as shown in figure 18-17. Table 18-6. Vibration source -
Main rotor
PROBLEM
FREQ (HZ)
PROBABLE CAUSE
CORRECTIVE ACTION
Low Frequency Oscillation
5.4
Worn pylon dampers
Replace worn dampers
Main Rotor Lateral in Flight
5.4
Main rotor out-of-balance
Balance main rotor
Main Rotor Vertical in Flight
5.4
Main rotor out-of-track
Track main rotor
Instrument Panel Vibration
10.8
Instrument panel support failure
Inspect instrument panel supports; replace or repair as necessary
Increased Cabin Vibration
10.8
Degraded skid gear supports
Inspect skid gear supports; replace degraded
assemblies 10.8
Loose battery
Inspect battery and battery deck, tighten and repair as
necessary 10.8
Degraded pylon mounts
Inspect pylon corner and fifth mount, replace degraded components
10.8
Swashplate freeplay
Inspect swashplate; replace worn bearings
Medium Frequency Vibration in Flight
27.7
Tail rotor out-of-track and balance
Track and balance tail rotor
Tail Rotor Balance Erratic
27.7
Loose tail rotor trunnion
Inspect and recenter tail rotor trunnion
Vibration in Pedals
7080
Chattering tail rotor boost
Replace tail rotor boost trunnion
Pulsating Noise in Cabin
110
Out-of balance main
Balance driveshaft
driveshaft High Frequency Vibration in Cabin or on Drivetrain
139
Rotor brake out-of-balance or support bearings worn
Inspect disk and bearings for damage or wear; replace damaged components
144
Oil cooler fan blades damaged
Inspect oil cooler fans; replace any damaged
components 18-00-00 Page 38
Rev. 5
BHT-212-MM
COMBINING GEARBOX LATERAL ACCELEROMETER
VERTICAL
l*,_
#3
#4
28 VDC LATERAL ACCELEROMETER DAU
PORT
ACC #2
PILOT SEAT RAIL VERTICAL ACCELEROMETER
CADU
212-M-18-17
Figure 18-17. RADS AT proper configuration
(VIBCHK)
Rev. 5
18-00-00 Page 39
BHT-212-MM 18-29.
1.
VIBCHK - RADS AT.
Ensure system is installed properly
(SPECTRUM) with a 250 Hz spectrum and a 1000 Hz spectrum for channels one through
four accelerometers installed at locations
(paragraph 18-28).
where suspected vibrations are felt.
2.
18-31.
Turn on CADU to view main screen.
Press QUIT until the main screen has been cleared of previous entries. Use arrow keys to select TYPE and and press press DO. DO. select HELICOPTER HELICOPTER TYPE Use arrow keys to highlight 212 and press DO. 3.
With helicopter type selected, press DO
to selected
or define TAIL NUMBER of
helicopter (BHT prefers operator to use S/N
AT 1.
Installation (SPECTRUM) - RADS
Install
and secure 29328200
DAU in
cabin aft of crew with connectors up. 2.
Identify
locations
where
abnormal
vibrations are felt and install (or hold by hand if possible) accelerometers.
and not registration number). When TAIL NUMBER has been highlighted or defined, press DO to select.
Connect end of 29105600 or 29105605 3. accelerometer cable to accelerometers. Route cable to DAU so it does not foul controls and
With helicopter type and tail number
is clear of engine exhaust. Connect opposite
4.
defined, select VIBCHK as the FLIGHT PLAN and press DO. 5.
Once the CADU is properly configured
end of cable to DAU port. 4. Connect 29104101 CADU to DAU using 29325601 communication cable.
for the VIBCHK, the CADU screen should look similar to example in figure 18-18. With CADU properly configured, press F1 to initiate MEASUREMENT mode of RADS.
5. Connect 29104700 28 VDC power cable to 28 VDC port on copilot side of pedestal. Connect opposite end of cable to 28 VDC connect on DAU.
6. Operate helicopter on both engines at 100 percent rpm and flat pitch. Obtain data at the four ground run conditions (GR). Once this data has been obtained conduct a flight
The RADS AT should now be installed 6. and ready to perform SPECTRUM test.
and obtain data in level flight at 110 knots
18-32.
using the flight acquisitions (FL) and the two 1000 HZ acquisitions (1KHz).
(SPECTRUM)-
7.
When all data has been collected, land
and shut down helicopter. If limits are exceeded refer to table 18-6 for probable cause of vibration and corrective action.
Vibration
troubleshooting
RADS AT.
1.
Ensure system is installed properly
2.
Turn on CADU to view main screen.
1
Press QUIT until the main screen has been cleared of previous entries. Use arrow keys to 8. When all data has been obtained and allLICOPTER press DO. select HELICOPTER TYPE TYPE and and press DO. corrective action completed remove all RADS Use arrow keys to highlight 212 and press AT hardware in accordance with paragraph DO. 18-22. 3.
With helicopter type selected, press DO
18-30. VIBRATION TROUBLESHOOTING
to select
(OPTIONAL) - RADS AT.
NUMBER has been highlighted, press DO to
TAIL
NUMBER.
When TAIL
select. The following paragraphs provide information
to help the operator isolate an unknown vibration and locate the source. Provided within the 212 software is a flight plan 18-00-00 Page 40
Rev. 5
4. With helicopter type and tail number selected, select SPECTRUM as the FLIGHT PLAN and press DO.
BHT-212-MM Once the CADU is properly configured,
5.
the CADU screen should look similar to
TAIL
18-34.
ROTOR
VIBRATION
MEASUREMENT INSTRUMENTATION.
example in figure 18-19. With CADU properly
configured,
press
F1 to initiate
SPECIALTOOLS REQUIRED
MEASUREMENT mode of RADS. Operate helicopter
6.
at test condition at
NOMENCLATURE
NUMBER NU
which problem is suspected and obtain on appropriate channels. Once this data has
29333300 o r Basic RADS AT kit 29133100 Scientific with basic software
been obtained, identify a test condition where the vibration is not as pronounced. Using a new flight I.D., obtain data at this condition.
Atlanta San Diego, CA 92123
7. When all data has been collected, land and shut down helicopter and review data and isolate the problem as follows:
a.
Look for the highest
peaks and
compare to and previous data to determine if they have changed.
29338500A 29338501 Atlanta
or
Scientific
2920330D or later Scientific Atlanta
b.
Compare
the problem
Atlanta 29328200
Scientific
c.
Compare suspected peaks to those
d.
Inspect,
service,
and/or replace
bracket Model 212/412 optical tracker bracket
Data Acquisition
Unit
(DAU) (included in basic RADS AT kit)
data to
shown in figure 18-20 to identify the source.
Optical rpm sensor
29329700 Scientific Accelerometer bracket
Atlanta determine which peaks have been reduced or which ones have disappeared. These are the peaks causing problems.
212 Version 4.20
Atlanta
Control and Data Unit (CADU)
991D Wilcox
Accelerometer (3 total)
Scientific
29105600 Scientific Accelerometer Atlanta
cable
50 foot (additional)
29105605 Scientific Accelerometer cable Atlanta 25 foot (additional)
assembly causing the problem.
8. Upon completion of test remove all RADS AT hardware in accordance with paragraph 18-22.
18-33.
18-35. Installation - RADS AT. Refer to BHT-ALL-SPM for specification and source.
TAIL ROTOR - TRACKING AND
MATERIALS REQUIRED REQUIRED MATERIALS
BALANCING.
The following paragraphs provide the necessary information to track and balance the tail rotor using the Scientific Atlanta Rotor Analysis and Diagnostic System, Model AT (RADS AT). The RADS AT automates the acquisition of blade track and vibration data
Refer to BHT-ALL-SPM for specification and source. NUMBER
NOMENCLATURE
C-483
Reflective tape
Position and install 29328200 DAU in
as well as corrective actions required to
1.
accomplish tracking and balancing.
cabin aft of crew seats with connectors up. 18-00-00 Rev. 5
Page
41
BHT-212-MM
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 3.10AP35D 18-APR-94
12:29:08
Aircraft Type
212 4.1
Tail Number Flight Plan Flight I.D.
35### VIBCHK
MEASURE
DISPLAY
DIAGS
MANAGER 212-M-18-18
Figure 18-18. Main rotor smoothing CADU screen (VIBCHK)
2. Remove nut from top stud position) on 90 degree gearbox install one 991D accelerometer connector up and secure with
accelerometer
(12:00 o'clock (figure 18-21); on stud with nut. Connect
end of 29105600
5. Connect 29104700 28 VDC power cable to 28 VDC port on copilot side of pedestal (figure 18-22). Connect other end of cable to 28 VDC connector on DAU.
accelerometer cable to vertical accelerometer.
6.
Route to DAU down left side of fin and
to DAU using 29325601 29325601 communications communications
tailboom. Secure cable so it cannot foul tail rotor or controls. Connect cable to port ACC #4 on DAU (figure 18-22). 3. Attach 29314700 optical rpm sensor to 29337400A tail rotor optical sensor bracket so
7.
Connect 29104700 28 VDC power cable
When correctly
installed, RADS AT
should be configured as shown in figures 1821 and 18-22.
wire is on flange edge of bracket. Secure sensor to bracket with MS21040-04 (#440) TEST TO BALANCE TAIL ROTOR.
self-locking nuts. Remove nut from aft stud on 90-degree gearbox and install sensor/bracket.
18-36.
Secure with gearbox nut so it is level to
1.
horizon and pointed directly aft (figure 18-21). Route optical sensor cable to DAU down left side of fin and tailboom. Secure cable so it cannot foul tail rotor or controls. Connect cable to port TACHO #2 on DAU (figure 18-
Press QUIT until the main screen has cleared entries. Use arrows to select of previous previous entries. Use arrows to select AIRCRAFT TYPE, TAIL NUMBER, select TAIL as the flight plan and press DO. The as shown in CADU sceen display will CADU screen display will be as shown in figure 18-23.
4. Install a full width piece of tape (C-483) between two blade bolts on gearbox side of blade (figure 18-21). This will be target blade. 18-00-00 Page
42
Rev. 5
Turn on CADU to view main screen.
Press F1 to initiate 2. mode.
MEASUREMENT
BHT-212-MM
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 3.10AP35D 18-APR-94
12:29:08
Aircraft Type Tail Number
212 4.1 35###
Flight Plan Flight I.D.
SPECTRUM
MEASURE
DISPLAY
DIAGS
MANAGER 212-M-18-19
Figure 18-19. Main rotor smoothing CADU screen (SPECTRUM)
3. Operate helicopter with one engine and stabilize rotor rpm as close to 100 percent as possible. Center cyclic, ensure collective is all the way down and the directional pedals are centered. With T/R highlighted press DO on
If all the above test conditions are OK and red light still does not illuminate, remove clear cover from
CADU to arm. If all internal checks are successful then the test condition title will
optical rpm sensor. Gently turn brass screw clockwise to increase gain until a slight click click is is felt. felt. With With
NOTE
appear at the bottom of screen. Press DO to
optical
rpm
view data. Press DO again to obtain data.
reflector
When data is obtained RADS AT will indicate test has been completed.
illuminate. cover.
4.
Select FINISH then DIAGNOSTICS to
6.
sensor
pointing
at
tape red light should Reinstall
clear plastic
If tail rotor balance is not acceptable
record predicted adjustments on form similar 18-24. Perform 18-7 for
review tail rotor 1/rev levels and determine if any adjustments are required. If TACH error
to one shown in figure
occurs while obtaining data, repeat test at
corrective action.
corrective action. Refer to table 18-7 for
least two times. 5. If failure occurs, shut down helicopter. Inspect reflective tape. Replace if necessary. With power to DAU verify red light on back of optical rpm sensor illuminates when reflector is in front of optical sensor. Verify that the optical rpm sensor is hooked to port TACHO #2.
7. Repeat steps 1. through 5. until tail rotor is balanced. NOTE The RADS AT is operating on preset limits of 0.20 IPS for tail rotor balance. If the operator desires to 18-00-00 Rev. 5
Page
43
BHT-212-MM SOURCE I.D. *
SOURCE
1 1 2
FREQ. (HZ)
FREQ. (CPM)
5.4 10.8 16.7 21.6 27.7
324 648 1000 1296 1662
1/REV 1/REV I/REV
41.5 43.2 51.5 55.3 66.7 71.7 71.7 71.7
2488 2592 3087 3324 4000 4302 4302 4302
1/REV 1/REV
75 75
4498 4498
HARMONIC 1/REV 2/REV
MAIN ROTOR MAIN ROTOR MRGB UPPER SUN GEAR MAIN ROTOR TAIL ROTOR
18
MRGB UPPER PLANETARY DEFECT MRGB UPPER RING GEAR DEFECT LOWER SUN GEAR/BEVEL GEAR (MRGB) TAIL ROTOR DEFECT ON LOWER RING GEAR HYDRAULIC PUMP TACH GENERATOR TAIL ROTOR DRIVESHAFT
3 4 5 18 7 12 13 15
TAIL TAKEOFF QUILL OIL PUMP (MRGB)
11 14
DEFECT ON UPPER SUN GEAR
2
90.2
5411.4
MAIN DRIVESHAFT NO. 2 HYDRAULIC PUMP
8 9
1/REV 1/REV
110 110
6600 6600
TAIL ROTOR DEFECT ON LOWER PLANETARY GEAR
21 6
4/REV
110.6 128
6640 7677
ROTOR BRAKE DISK DEFECT ON LOWER SUN GEAR
10 5
1/REV
138.7 139.2
8322 8351
TAIL ROTOR DRIVESHAFT OIL COOLER FAN POWER TURBINE/CBOX INPUT GAS GENERATOR-LOW
18
2/REV I/REV 1/REV 1/REV
143.4 143.8 550 508
8604 8630 33000 30480
1/REV
635
38100
2,3,4 17 11,15 12 5,6,7 11 16 5,8
GEARMESH GEARMESH GEARMESH GEARMESH GEARMESH GEARMESH GEARMESH GEARMESH
642 1578 1649 1864 1983 2624 2725 3190
38543 94660 98964 111852 119000 157442 163505 191400
GAS GENERATOR-HIGH
UPPER PLANETARY 90 DEGREE GEARBOX TAIL TAKEOFF HYD. DRIVE QUILL LOWER PLANETARY TAIL TAKEOFF QUILL 42 DEGREE GEARBOX INPUT BEVEL GEAR
4/REV 1/REV
2/REV
*SEE SHEET 2
212-M-18-20-1
Figure 18-20.
18-00-00 Page 44
Rev. 5
Excitation frequencies (Sheet 1 of 2)
BHT-212-MM
OUTPUT TO MAIN ROTOR
OUTPUT TO TAIL ROTOR
212-M-18-20-2
Figure 18-20. Excitation frequencies (Sheet 2)
Rev. 5
18-00-00 Page 45
BHT-212-MM ACCELEROMETER LOCATEDAT 12 O'CLOCK WITH CONNECTORUP
OPTICAL SENSOR LOCATEDAT 9 O'CLOCK WITH LENSTOWARD TAIL ROTOR
TARGET BLADE
REFLECTIVETAPE LOCATEDBETWEEN BLADE BOLTSON SIDE OF TARGET BLADE NEXT TO TAIL FIN 212-M-18-21
Figure 18-21. Accelerometer and optical sensor installation - Tail rotor
18-00-00 Page
46
Rev. 5
BHT-212-MM
90 DEGREE GEARBOX VERTICAL ACCELEROMETER AC #4
TACHO #2
OPTICAL RPM SENSOR CADU
PEDESTAL 28 VDC DAU
PORT
212-M-18-22
Figure 18-22. Tail rotor - proper RADS AT installation
reduce the level to below 0.20 IPS then this can be done by pressing DO from limits screen. The RADS AT will specify adjustments required to achieve a 0 IPS balance. 8. If tail rotor balance is acceptable remove RADS AT from helicopter (paragraph 18-38). 18-37.
Tail rotor balance adjustments.
RADS AT specifies balance adjustments required to balance tail rotor as adjustments made only to target blade. There are three
adjustments available; outboard blade bolt,
have both blade bolts on at the same time and never edit the blank adjustments. Once adjustments to target blade have been defined, determine what moves can be made. If RADS AT specifies to add weight to a location where weight is on opposite blade, the proper course is to remove required amount from opposite location. If RADS AT specifies to remove weight from location that does not have weight, add weight to opposite side. 1. Review the location and size of currently installed weights. It is best to remove weight when possible. It is acceptable to install
weights
on both sides to make small
inboard blade bolt, and chordwise balance. The default in the RADS AT software is to use only chord and outboard bolt. Should the
adjustments.
operator need to use the inboard bolt for balance, then from within DIAGNOSTICS, select EDIT ADJUSTABLES from menu. Use
installed to which adjustments are to be made. Using hardware listed in table 18-2 create or adjust the weight package to
F1 to turn off outboard blade bolt (by
changing Y to N) and then use F1 to turn on inboard blade bolt on target blade only (N to
Y). Pressing DO will automatically recalculate corrections
using inboard blade bolt. Never
2.
Remove any weight package
already
achieve the desired amount of balance change. The gram scale supplied with the RADS AT can be used to obtain the desired
adjustment. Install balance weights and torque in accordance with Chapter 64. 18-00-00 Rev. 5
Page
47
BHT-212-MM
washers (thick aluminum washer next to
18-38. Removal - RADS AT.
gearbox) and torque 50 to 70 inch-lbs. (5.65 to 7.91 Nm).
1. Disconnect 29104700 28 VDC power cable from 28 VDC port on copilot side of pedestal and from DAU. Disconnect 29325601 communication 2. cable from DAU and 29104700 power cable.
4.
from gearbox. Install new nut and washer and torque 50 to 70 inch-lbs. (5.65 to 7.91 Nm).
5. 3. Remove optical rpm sensor and bracket from tail rotor gearbox. Install new nuts and
Remove 991 D accelerometer and bracket
Remove DAU from cabin aft of crew
seats.
Table 18-7. Vibration source -
Tail rotor
FREQ
(HZ)
PROBABLE CAUSE
CORRECTIVE ACTION
10.8
Degraded pylon mounts
Inspect pylon corner and fifth mount, replace degraded components
10.8
Swashplate freeplay
Inspect swashplate, replace worn bearings
Medium Frequency Vibration in Cabin
27.7
Tail rotor out-of-track and balance
Track and balance tail rotor paragraph 18-32
Tail Rotor Balance Erratic
27.7
Loose tail rotor trunnion
Inspect and recenter tail rotor trunnion
Vibration in Pedals
70-
Chattering tail rotor boost
Replace tail rotor boost
80
cylinder
cylinder
110
Out-of-balance main
Balance driveshaft
PROBLEM
Pulsating Noise in Cabin
driveshaft High Frequency Vibration in Cabin or on Drivetrain
18-00-00 Page
48
Rev. 5
139
Rotor brake out-of-balance or support bearings worn
Inspect disc and bearings for damage or wear, replace damaged components
144
Oil cooler fan blades damaged
Inspect oil cooler fans, replace any damaged components found
BHT-212-MM
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 3.10AP35D 18-APR-94
12:29:08
Aircraft Type
212 4.1
Tail Number Flight Plan Flight I.D.
35### Tail
MEASURE
DISPLAY
DIAGS
MANAGER 212-M-18-23
Figure 18-23. Tail rotor smoothing CADU screen
Rev. 5
18-00-00 Page 49
BHT-212-MM
BLANK =
TARGET =
SHIP S/N = RADS AT FLIGHT I.D.
BLADE I.D.
BLADE BOLT
CHORD BALANCE
I/REV READING
DATE =
TARGET
TIME= BLANK
NOTES ON PREVIOUS RUN:
RADS AT
BLADE
BLADE
CHORD
I/REV
FLIGHT I.D. DATE =
I.D.
BOLT
BALANCE
READING
BLADE BOLT
CHORD BALANCE
I/REV READING
TARGET TIME = BLANK
NOTES ON PREVIOUS RUN:
RADS AT FLIGHT I.D.
BLADE I.D.
DATE =
TARGET
TIME= BLANK NOTES ON PREVIOUS RUN:
RADS AT
BLADE
BLADE
FLIGHT I.D.
I.D.
BOLT
CHORD
BALANCE
1/REV
READING
DATE =
TARGET TIME = BLANK
NOTES ON PREVIOUS RUN: 212-M-18-24
Figure 18-24. Tail rotor adjustment log
18-00-00 Page 50
Rev. 5
BHT-212-MM
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
TORQUE 60 IN-LBS (6.78 Nm) SEENOTES 1 AND 3
14
Blade bolt (outboard) Washer (140-007-33-32C4) Tail rotor blade Washer (140)007-33-32C4) Washer (212-010-764-1) Washer (AN970-8) Washer (AN960-816) Washer (AN960-816L) Nut Bolt Washer (AN960-416)
12. Washer(AN970-4) 13. Dynamic balance bracket
14. Washer (AN970-4) TORQUE
15. Washer (AN960-416)
500 TO 550 IN-LBS. (56.49TO 62.14 Nm) SEENOTE 2
16. Nut
NOTES 1. Listing of weight, in grams, of individual components used for balance.
NOMENCLATURE
WEIGHT
NOMENCLATURE
WEIGHT
NAS1304-2 Bolt
5.81 gm.
AN960-416 Washer
1.16gm.
NAS1304-3 Bolt
6.17 gm.
AN960-16 Washer
3.22 gm.
NAS1304-4Bolt
6.54 gm.
AN960-816L Washer
1.63 gm.
NAS1304-5 Bolt
6.90 gm.
AN970-4 Washer
7.54gm.
NAS1308-34 Bolt
87.60 gm.
AN970-8 Washer
37.80 gm.
NAS1308-36 Bolt
90.80 gm.
MS21042L4-Nut
1.59 gm.
2. For spanwise dynamic balance, use NAS1308-34 through NAS1308-36 bolts (1) as required to accomodate balance washers. Bolts may be installed with head, inboard or
outboard, but all four blade bolts must be installed the same. When change of balance washers and/or bolts is required, ensure that one washer (2) and one washer (4) are installed next to blade as illustrated. Then install heaviest balance washers next to washer (4). Install the above listed parts on blade (3) or on opposite blade as required to obtain balance. 3. For chordwise dynamic
balance, use NAS1304-1, -2, -3, -4,
-6, -8,-10, -12, or-14 bolts (10)as required to accomodate balance washers (11 12, 14, and 15). Use a maximum of two AN970-4 washers (12 and 14) and a maximum of ten AN960-416 washers (11 and 15) on one bracket Install washers symmetrically. Install the above listed parts on
bracket (13) or opposite bracket (not illustrated) as required to obtain balance.
212-M-18-25 212-M-18-25
Figure 18-25. Tail rotor balance hardware
Rev. 5
18-00-00 Page 51
BHT-212-MM Table 18-8. Balancing hardware-
Tail Rotor
ITEM
IDENTIFICATION
WEIGHT
NUMBERED REQUIRED
RADS AT Basic Kit
29333300 or later
N/A
One (1)
Optical RPM Sensor Bracket
29338500a or 29313100
N/A
One (1)
Stiff Accelerometer Brackets
29329700 or c-h #6752
N/A
Two (2)
Bolt for One Weight
AN5-12A
2 grams
As required
Bolt for Two Weights
AN5-13A
4 grams
As required
Balance Weight
100-106-1
14.18 grams
As required
Balance Weight
100-106-2
7.09 grams
As required
Balance Weight
100-106-3
2.84 grams
As required
18-39.
SPECIAL TOOLS REQUIRED (CONT)
MAIN DRIVESHAFT BALANCING.
The following paragraphs provide the necessary information to balance the
NUMBER
driveshaft using the Scientific Atlanta Rotor Analysis And Diagnostic System, Model AT
29314101 Atlanta
accomplished while performing main rotor tracking and balancing (using two extra
or Optical RPM sensor 29338500A 29338501 Scientific bracket
accelerometers and cables) or as a separate test.
Atlanta
(RADS AT). This procedure
18-40.
may be
DRIVESHAFT VIBRATION
Scientific
Scientific
991D Wilcox
MEASUREMENT INSTRUMENTATION. 18-41.
29329700 Atlanta
NOMENCLATURE Control and Data Unit (CADU)
Accelerometer bracket Accelerometer (2 total)
29105600 Scientific Accelerometer Installation of RADS.
Atlanta
29105605 Scientific Accelerometer Atlanta (25 foot)
SPECIAL TOOLS REQUIRED NUMBER
NOMENCLATURE
2 9 3 3 3 3 0 0
o r
Basic
RADS
AT
kit
29313100 Scientific with basic software Atlanta San Diego, CA 92123
212 version 4.20
29328200
Data acquisition
Scientific
Atlanta
(DAU) (included basic kit)
18-00-00 Page 52
Rev. 5
Unit
in
cable
(50 foot)
cable
29314101 Atlanta
Scientific
Power cable (28 VDC)
29325601
Scientific
Communication
cable
BHT-212-MM
MATERIALS REQUIRED
not rotate and contact main driveshaft. Route and secure cable to DAU ensuring it can not foul any rotating components. Connect cable to DAU port TACHO #2.
Refer to BHT-ALL-SPMfor specification and source.
6. With optical sensor installed, turn driveshaft so one shaft-to-adapter bolt is
Refer to BHT-ALL-SPM for specification and source.
NUMBER
NOMENCLATURE
C-483
Reflective tape
directly on top. With driveshaft in this position, center and install a three inch piece of tape (C-483) on shaft with long axis of tape aligned
with long axis of driveshaft and centered
1. Position and install 29328200 DAU in cabin aft of crewseats, with connectors up.
relative to shaft-adapter bolt and under optical sensor. The bolt aligned with reflector is bolt #1 (figure 18-28).
2. Install one 991D accelerometer using 29329700 bracket on right side of combining
7. Connect 29314101 28 VDC power cable to 28 VDC port on copilot side of pedestal. Connect other end of cable to 28 VDC
accelerometer cable to combining gearbox accelerometer. Route and secure cable so
8. Connect CADU to DAU using 29325601 communications cable.
gearbox (figure 18-26). Connect accelerometer end of 29105600
connector on DAU.
cannot foul any rotating components, and connect opposite end to DAU port ACC #3. 3. Using a 29329700 accelerometer bracket, install one 991D accelerometer on stud at 1 o'clock position of transmission input quill by removing Allen head screw and using a 1/4 X 28 bolt to secure accelerometer laterally as shown in figure 18-26. Connect
accelerometer
end of 29105600
9.
The RADS is now installed and ready to
balance driveshaft. When correctly installed, RADS AT should be configured as shown in figure 18-29. 18-42. AT.
Balancing main driveshaft - RADS
Ensure system is properly installed
accelerometer cable to transmission input
1.
quill accelerometer, route and secure to DAU so it can not foul any rotating components and connect opposite end to DAU port ACC
(figure 18-29). 2.
#4.
screen, Press QUIT until main screen is
4. Using nut (4, figure 18-27), rpm sensor optical 29314700 29338500A or 29338501 optical rpm bracket (7) with clear lens adjacent to
attach (8) to sensor vertical
attachmentleg. 5.
Using nut (2), washer (1) and washer (6),
Turn
on CADU and, from
the main
cleared of previous entries. Use arrow keys to select AIRCRAFT TYPE and press DO. Use arrow keys to highlight 212 and press DO. 3.
With helicopter type selected, press DO
to select TAIL NUMBER. When TAIL NUMBER has been highlighted, press DO to select.
and bolt (5), attach 29314700 optical rpm sensor to tail rotor driveshaft 29337500A
4.
optical sensor bracket (7) to right hand inlet cowl alignment flange of transmission firewall
selected, select D/S as the FLIGHT PLAN and press DO.
(3). Align optical rpm sensor bracket in horizontal position directly over main driveshaft so that clear lens is level and
5. Once the CADU is properly configured for the D/S mode, the screen should look
pointed to the left. Tighten nut until bracket cannot move Tiewrap optical rpm sensor to a convenient point above to ensure bracket will
similar to example in figure 18-30. With CADU press F1 to initiate properly configured, MEASUREMENT MODE OF rads at.
With helicopter type and tail number
Rev. 5
18-00-00 Page 53
BHT-212-MM
STUD USED TO INSTALL ACCELEROMETER BRACKETLOCATED FORWARD AND BELOW NO. 2 ENGINE TRIM COMPENSATOR(ACCELEROMETER/BRACKETNOT INSTALLED)
LOCATION OF ACCELEROMETERAT THE
NOT INSTALLED) (ACCELEROMETER/BRACKET
212-M-18-26
Figure 18-26. Combining gearbox and transmission input quill accelerometers
18-00-00 Page 54
Rev. 5
BHT-212-MM
ATTACH OPTICAL RPM SENSOR BRACKET TO RIGHT INLET COWL ALIGNMENT FLANGE
1.
Washer
2. 3.
Nut Transmission
firewall 4.
Nut
5.
Bolt
6. Washer 7. Optical rpm sensor bracket 8. Optical rpm sensor
212-M-18-27
Figure 18-27. Optical rpm sensor and bracket
Rev. 5
18-00-00 Page 55
BHT-212-MM 6. Operate helicopter with both engines and stabilize the main rotor at 100% percent rpm
11. Repeat steps 1. through 9. until main driveshaft is balanced.
and increase torque to 30 percent. Center cyclic and directional pedals.
NOTE The RADS AT is operating on preset limits of 0.20 IPS for main driveshaft balance. If the operator desires to reduce the level to below 0.20 IPS then this can be done by pressing DO from limits screen. The RADS AT will specify adjustments required to achieve a 0 IPS balance.
NOTE On initial run, operate the helicopter for at least five minutes prior to taking tests. With D/S highlighted, press DO to arm 7. RADS AT. If all internal checks are successful
the test condition title will appear at the bottom of the screen and system is armed to take data. Press DO to obtain data. If data has been successfully obtained, the RADS AT will indicate that the test is complete.
12. If main driveshaft balance is acceptable, remove RADS AT from helicopter (paragraph 18-43).
18-43. If a TACH error occurs during testing, repeat test at least four times. If failure still occurs, proceed to next step. 8. If failure still occurs after repeating test four times: a. Ensure reflective tape is in place and clean. Replace if necessary. b. With power to DAU, verify that the red light on back of optical rpm sensor illuminates when the reflective tape is in front of optical rpm sensor.
The RADS AT specifies corrections for main driveshaft balance as adjustments to balance weights on the aft and forward driveshaft shaft-to-adapter bolts as shown in figure 1829. As programmed, the RADS AT version 3.1 specifies adjustments only to #1 and #3 bolts. To specify adjustments for bolt #2, the EDIT
ADJUSTABLES mode shall be used. The shaft is balanced by installing or removing 1.
Once bolt to be adjusted has been
determined, remove nut and bolt and using boltweight bolt/weight combination combination shown shown in in table table 18-10, 18-10, configure a weight package closest to weight specified by RADS AT.
Ensure that optical rpm sensor is NOTE
connected to DAU port TACHO #2. Orient helicopter so that sensor is in d. shadow (not in direct sunlight). 9. Select FINISH and then DIAGNOSTICS to review main driveshaft 1/rev levels and determine if any adjustments are required.
10.
If main driveshaft
balance is not
acceptable, record predicted adjustments on form similar to one shown in figure 18-31. Perform corrective action. Refer to table 18-9 for corrective action. 18-00-00 Page
balance
adjustments.
NOTE
c.
Main driveshaft
56
Rev. 5
Bolt to referenced are referenced Bolt weights are minimum bolt size used. AN5-11A bolt shall be used when no weights are installed; AN5-12A bolt shall be used when one weight is installed, and the AN5-13A bolt shall be used when two weights are installed. Maximum stackup of weights is two
per bolt. 2. Install bolt/weight package with weights under nut. Torque nuts 100 to 140 in lbs. (11.30 to 15.82 Nm).
BHT-212-MM
RADS REFLECTOR
LOOKING AFT
BOLT#1
REFLECTIVE TAPE UNDER OPTICAL RPM SENSOR ALIGNED WITH BOLT #1
NOTES
1.
Bolt orientation shown is used to determine placement of balance weights
from chart information. 2.
Bolt #1 is bolt aligned with the reflective tape on the tube.
3.
Bolt #1 and #3 are active in rads diagnostics.
4.
Adding weight to bolt #1 is same as removing weight from bolt #4.
5.
Adding weight to bolt #3 is same as removing weight from bolt #6. 212-M-18-28
Figure 18-28. Reflective tape installation, main driveshaft
Rev. 5
18-00-00 Page 57
BHT-212-MM
COMBINING GEARBOX LATERAL
TRANSMISSION INPUT QUILL LATERAL
CADU
CH4
DATA ACQUISITION UNIT (DAU)
PEDESTAL
OPTICAL RPM SENSOR
TACHO#2
28 VDC
212-M-18-29
Figure 18-29. RADS AT configuration for balancing main driveshaft
18-00-00 Page 58
Rev. 5
BHT-212-MM
SCIENTIFIC ATLANTA - STEWART HUGHES RADS AT VERSION 3.10AP35D 18-APR-94 12:29:08 Aircraft Type Tail Number Flight Plan Flight I.D.
MEASURE
212 4.1 35### D/S
DISPLAY
DIAGS
MANAGER 212-M-18-30
Figure 18-30. Main driveshaft balancing CADU screen
3.
Repeat procedures of paragraph 18-43
until main driveshaft is balanced.
5.
Remove
29329700
991D
accelerometer
accelerometer
and
bracket
from
combining gearbox quill. 18-44.
Removal - RADS AT.
6.
Remove DAU from cabin aft of crew
seats. 1. Disconnect 29314101 28 VDC power cable from 28 VDC port on copilot side of
pedestal and from DAU.
18-45.
GENERAL VIBRATION
CHECK
(OPTIONAL) - RADS AT.
2.
Disconnect 29325601 communication
cable from DAU and CADU.
3. Remove 29314700 optical rpm sensor and 29338500 or 29338501 optical rpm
.
For procedures to perform vibration (VIBCHK), refer to paragraph 18-29.
check
18-46. VIBRATION TROUBLESHOOTING
sensor bracket from right inlet cowl alignment flange of transmission firewall.
(OPTIONAL) - RADS AT.
4. Remove 991D accelerometer and 29329700 accelerometer bracket from
For procedures to perform vibration troubleshooting (SPECTRUM), refer to
transmission input quill.
paragraph 18-31. Rev. 5
18-00-00 Page 59
BHT-212-MM
SHAFT END
RADSAT FLIGHT I.D. DATE =
1/REV LEVEL
BOLT #1
BOLT #2
BOLT #3
BOLT #4
BOLT #5
BOLT #6
BOLT
BOLT
BOLT
BOLT
BOLT
BOLT
1/REV
#1
#2
#3
#4
#5
#6
LEVEL
AFT
TIME= FORWARD NOTES ON PREVIOUS RUN:
SHAFT
RADS AT
END
FLIGHT I.D.
DATE= AFT
TIME= FORWARD NOTES ON PREVIOUS RUN:
RADS AT
SHAFT
BOLT
BOLT
BOLT
BOLT
BOLT
BOLT
FLIGHT I.D.
END
#1
#2
#3
#4
#5
#6
1/REV LEVEL
DATE = AFT
TIME= FORWARD NOTES ON PREVIOUS RUN:
RADSAT
SHAFT
BOLT
BOLT
BOLT
BOLT
BOLT
BOLT
I/REV
FLIGHT I.D.
END
#1
#2
#3
#4
#5
#6
LEVEL
DATE = AFT
TIME= FORWARD 212-M-18-31
NOTES ON PREVIOUS RUN:
Figure 18-31.
18-00-00 Page
60
Rev. 5
Main driveshaft adjustment log
BHT-212-MM Table 18-9. Vibration source-
Driveshaft
PROBLEM
FREQ (HZ)
PROBABLE CAUSE
CORRECTIVE ACTION
Low Frequency
5.4
Worn pylon dampers
Replace pylon dampers
Main Rotor Lateral in Flight
5.4
Main rotor out-of-balance
Balance main rotor
Main Rotor Vertical in Flight
5.4
Main rotor out-of-track
Track main rotor
Instrument Panel Vibration
10.8
Instrument panel support failure
Inspect instrument panel supports, replace or repair as necessary
Increased Cabin Vibration
10.8
Degraded skid gear supports
Inspect skid gear supports, replace degraded assemblies
10.8
Loose battery
Inspect battery and battery deck, tighten and repair as necessary
10.8
Degraded pylon mounts
Inspect pylon corner and fifth mount, replace degraded components
10.8
Swashplate freeplay
Inspect swashplate, replace worn bearings
Medium Frequency Vibration in Cabin
27.7
Tail rotor out-of-track and balance
Track and balance tail rotor
Taill Rotor Balance Erratic
27.7
Loose tail rotor trunnion
Inspect and recenter tail rotor trunnion
Vibration in Pedals
7080
Chattering tail rotor boost cylinder
Replace tail rotor boost cylinder
Pulsating Noise in Cabin
110
Out-of-balance main driveshaft
Balance driveshaft paragraph 18-41
High Frequency Vibration in Cabin or on Drivetrain
139
Rotor brake out-ofbalance or support bearings worn
Inspect disc and bearings for damage or wear, replace damaged components
144
Oil cooler fan blades damaged
Inspect oil cooler fans, replace any damaged components
Oscillation
18-00-00 Rev. 5
Page
61
BHT-212-MM Table 18-10. Hardware and Weight -
Driveshaft WEIGHT
GRAMS
OUNCES
PART NO.
NAME
AN5-12A
Bolt
2.00
0.07
AN5-13A
Bolt
4.00
0.14
100-106-1
Plate, balance weight
14.18
0.50
100-106-2
Plate, balance weight
7.09
0.025
100-106-3
Plate, balance weight
2.84
0.10
18-00-00 Page 62
Rev. 5
BHT-212-MM
CHAPTER 21 -
AIR DISTRIBUTION (VENTILATION)
CONTENTS Paragraph Number
21-1 21-2
MAINTENANCE PROCEDURES
Title
Chapter/Section Number
Page Number
21-00-00 21-00-00
3 4
21-00-00 21-00-00 21-00-00 21-00-00
7 7 7 10
Air distribution (ventilation) ....................... Troubleshooting ................................ BLEED AIR HEATING SYSTEM COMPONENTS
21-3 21-4 21-7 21-10
Bleed air heating system components ............ Bleed air shutoff valve ......................... Variable control mixing valve ................... Remote Sensor ................................
21-13
Selector ........................................
21-00-00
10
21-16 21-19
Outlet control valve ............................ Heat/vent air ducts .............................
21-00-00 21-00-00
11 11
21-00-00 21-00-00
15 15
VENTILATION/DEFOG SYSTEM 21-23 21-24
Ventilation/defog system .......................... Ventilation blower .............................. FIGURES
Figure Number 21-1 21-2 21-3 21-4
Title Air distribution system schematic (typical) .................................. Bleed air heating system (S/N 30504 through 30553) ....................... Bleed air heating system (S/N 30554 and sub.) ............................. Outlet control valve ..........................................................
Page Number 6 8 9 13
TABLES Table Number
21-1
Title
Troubleshooting..............................................................
Page Number
4 21-00-00 Page
1
BHT-212-MM
CONSUMABLE MATERIAL LIST The following consumable materials are required to perform the maintenance procedures within this chapter. ITEM NO.
NOMENCLATURE
CAGE/FSCM/ SOURCE
C-300
Adhesive, 299-947-152, Type I, Class I (Dapcotac 3300)
97499
C-306
Toluene, TT-T-548
Commercial
C-314
Adhesive, 299-947-152, Type III or RTV 20-046 or 94-002
97499 01139
C-347
Xylene TT-X-916, Grade A
Commercial
C-403
Glass Cloth, Scotchbrand 361, Flame Resistant
76381
C-404
Glass Cloth, 0.010 inch thick, MIL-C-9084
Commercial
C-405
Lockwire, MS20995C32 (0.032 Inch Dia.)
Commercial
C-439
Aluminum Foil Tape, No. 425
26066
21-00-00 Page 2
BHT-212-MM
AIR DISTRIBUTION (VENTILATION)
21-1. AIR DISTRIBUTION (VENTILATION).
The temperature selecting dial, through an electrical positioning motor, controls a remote sensor which is mounted on plenum chamber
The cabin air distribution system includes two subsystems which provide optional use of
in compartment on right side below engine deck. This sensor using a bimetallic element, senses temperature in heater duct and controls mixing valve through a small
heated or ventilation air from separate sources directed through the same ducting.
tube which operates a bleed port valve.
Functional
separation of the systems is
When heater-defrost lever, on front right
obtained by flow actuated Y-valves located under the windshield defrost-defog nozzles.
pedestal, is moved forward to ON, a valve in base of pedestal is closed by linkage to shut
Refer to figure 21-1 for air distribution system ~pedestal Heated air for cabin heating and defrosting windshields is provided by bleed air from
power section compressors.
The system
pumps air through ducting to outlets at both door posts, either side of center pedestal, each side of instrument panel, lower forward window nozzles, and left and right windshield defrosting nozzles. Heating is controlled by switches on overhead console, a temperature selecting dial on right side door post, and
heater defrost control lever on right side of
Ventilating-defogging system uses ram air as source from intake grilles on cabin nose, with optional use of blowers for windshield nozzle and outlets ahead of crew stations. Air intake
off off heated heated air air flow flow to to the the four four vales vales in in
base. Simultaneously, lever linkage activates a micro-switch in base and closes two valves on single shaft in air distribution outlet control valve and shuts off heated air flow to passenger compartment valves. When lever aft to OFF, the reverse actions occuristomoved open the valves. occur to open the valves. Engine compressor air flow noise is muffled by a noise suppressor in rear of fuselage forward of the mixing valve. Heated air exits from the noise suppressor into a plemun chamber aft of the cabin area. A temperature limit switch in aft cabin prevents overheating.
If If temperature temperature in in plenum plenum exceeds exceeds 220°F 220 (104.4°C), the limit switch activates MASTER CAUTION light and HEATER AIR LINE segment in caution panel. Cycling continues until heater is turned off or problem is corrected.
is controlled by actuating a cable knob. Blowers are controlled by an overhead panel switch.
21-00-00 Page 3
BHT-212-MM
21-2.
TROUBLESHOOTING.
Troubleshoot bleed air heating system in accordance with table 21-1. Table 21-1.
Troubleshooting
INDICATION OF TROUBLE
PROBABLE CAUSE
CORRECTIVE ACTION
No bleed flow to mixing valve.
Ruptured bleed air line.
Repair damaged line.
No voltage to bleed air valve.
Refer to Chapter 96.
Bleed air valve stuck.
Replace valve.
No voltage to mixing valve.
Refer to Chapter 96.
Inadequate air pressure.
Repair leakage in line from
No bleed air flow through mixing valve.
mixing valve to sensor. Inoperative mixing valve.
Temperature
of heated
If bleed air and voltage exists, replace mixing valve.
Faulty selector dial cable Replaceand cable assembly.
ventilation air will not assembly. modulate.
Ventilation air all hot.
Ventilation air all cool.
Faulty temperature sensor.
Replace sensor unit.
Plugged sensor line from mixing valve to sensor.
Clear line.
Faulty temperature sensor.
Replace sensor unit.
Faulty temperature dial cable.
selector
Faulty temperature sensor.
Replace cable assembly.
Replace sensor unit. Check for leaking sensor line and repair.
No air out of door post
No voltage to door post outlet Repair wiring (Chapter 96).
outlets.
valve.
21-00-00 Page 4
BHT-212-MM
Table 21-1. INDICATION OF TROUBLE
(Cont)
PROBABLE CAUSE Inoperative console.
limit switch
CORRECTIVE ACTION on
Refer to Chapter 96.
Unable to shut off air to door post outlets.
No voltage to door post outlet valve.
Refer to Chapter 96.
HEATER AIR LINES caution
Defective overheat switch or
Replace switch or repair wiring
segment
illuminates
- wiring.
(Chapter 96).
HEATER switch ON or OFF. HEATER AIR LINES caution segment illuminates when
HEATER switch is ON. Heater system operating
Defective overheat switch or wiring.
Replace switch or repair wiring (Chapter 96).
normally.
GENUINE BELL PARTS ARE YOUR BEST VALUE Rev.3
21-00-00 Page 5
BHT-212-MM
VENTURI BLEEDAIR SHUTOFF
~
AND LINE CHECK VALVE
SOLENOID
AMBIENTAIR INTAKE
MIXINGVALVE TEMP CONTROLSWITCH (OVERHEAT SWITCH) NOISE SUPPRESSOR--
/-
REMOTESENSOR
MOTOR POSITIONING
SWITCH OVERHEAT OUTLET CONTROL
VALVE
PLENUM
SELECTOR
DOORPOSTHOUSED
DEFROSTHANDLE MICRO SWITCH
WINDSHIELD DEFOG VALVE
VENT AIR INLET
BLOWER (VENT)
212-M-21-1
Figure 21-1. Air distribution system schematic (typical)
21-00-00 Page 6
BHT-212-MM
BLEED AIR HEATING SYSTEM COMPONENTS 21-3. BLEED AIR HEATING SYSTEM COMPONENTS.
21-6.
MATERIALS REQUIRED
The following paragraphs provide maintenance information for various miscellaneous
components.
These
procedures are typical for all serial number helicopters. Minor differences may exist due
Installation.
NUMBER
NOMENCLATURE
C-314
Adhesive
to helicopter configuration and various kits which may be installed. 21-4.
1. Position valve in place on engine deck
BLEED AIR SHUTOFF VALVE.
and install B nut under deck. Torque 40 to 58 ft.lbs. (54.23 to 78.63 Nm).
NOTE
2. Connect Y-tube assembly, electrical connector and bleed air line from engine
Refer to figure 21-2 for S/N 30504 through 30553 and figure 21-3 for S/ N 30554 and sub. Two bleed air shutoff valves are installed on
compressor. 3. Use adhesive (C-314) or equivalent, install shroud over connections.
to
engine deck to control air flow to cabin heating system. Valves are opened by 28 Vdc to actuate a solenoid and are closed by air pressure.
NOTE Maintenance Maintenance procedures procedures for for both both
bleed air shutoff valves are the same. The following procedures are forsame.Thalve (3, following 21-3). procedures are
21-7. VARIABLE CONTROL MIXING VALVE. The mixing valve (5, figure 21-2 and 21-3) is installed on the right side below the engine
deck. This valve controls bleed air and ambient air flow as directed by the remote sensor (18). A bleed air nozzle inside the mixing valve acts as a jet pump through a venturi to draw in ambient air and control the mixed air flow. When heated air is not at the
21-5. Removal.
selected temperature, the remote sensor causes the variable control mixing valve to increase or decrease engine bleed air flow
1.
Disconnect Y-tube assembly (1, figure 21-
and to regulate ambient air flow as required to
2 or figure 21-3) from shutoff valve (3) through large access under engine deck at
correct the temperature variation. A temperature limit switch (6) is located on
underside of fuselage.
mixing valve to protect the structure from damage if a distribution system duct ruptures. This switch is set at 220°F (104°C). If this temperature is exceeded, the CABIN HTR circuit breaker will open.
2. Remove B nut below engine deck and on engine deck remove electrical connector and bleed air line from engine compressor. 3.
Remove valve from airframe.
21-8.
Removal.
1. Open access door at rear of fuselage under engine compartment to gain access to heater compartment. 21-00-00 Page 7
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Y Tube Assembly Tube Assembly Bleed Air Shutoff Valves Air Intake Variable Control Mixing Valve Overheat Temperature Switch Duct Noise Suppressor Coupling Plenum Overheat Temperature Switch Duct Duct
14.
Duct
15. 16. 17. 18. 19.
Selector Outlet Control Valve Sensing Line Sensor Duct
20.
Duct
21. 22. 23.
Duct Elbow Valve and Duct Assembly
24.
Duct
25.
Valve and Duct Assembly
26.
Selecting Dial and Cable
27. Duct Assembly 28.
Windshield Nozzle
29. Ventilation Air Outlets
211
30. 31.
Valve Assembly Duct Assembly
32.
Ventilation Control Cable
34.
Duct
35. 36.
Valve Assembly Heat-Defrost Control Lever
37.
Heated Air Outlets
38.
Lower Window Nozzle
39. 40.
Ventilating Air Intake Plenum Drain
41.
Heat-Defrost
Selector Valve
212-M-21-2
1. "Y" Tube Assembly
2. Tube Assembly 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Bleed Air Shutoff Valves Air Intake Variable Control Mixing Valve Overheat Temperature Switch Duct Noise Suppressor Coupling Plenum Overheat Temperature Switch Duct Duct Duct
15. Selector 16. Outlet Control Valve 17. Sensing Line 18. Sensor
19. Duct
20. Duct 21. 22. 23. 24.
Duct Elbow Valve and Duct Assembly Duct
(17) 7
25. 26. 27. 28. 29. 30. 31. 32. 33.
Valve and Duct Assembly Selecting Dial and Cable Duct Assembly Windshield Nozzle Ventilation Air Outlets Valve Assembly Duct Assembly Ventilation Control Cable Blower
e4. Duct (23)35.
2
3041.
Valve Assembly Heat-Defrost Control Lever Heated Air Outlets Lower Window Nozzle Ventilating Air Intake Plenum Drain Heat-Defrost Selector Valve 42. Duct 36. 37. 38. 39. 40.
212-M-21-3
BHT-212-MM
2.
Remove two sensing lines, on-off valve
wiring and overheat temperature switch (6,
3.
Phase
controller
sensor
and motor
(Chapter 96).
figure 21-2 or figure 21-3) wiring. 3. Disconnect tube, remove clamp, large B nut and attaching hardware and remove valve (5).
21-9. Installation. 1. Position valve (5, figure 21-2 or figure 213) in heater system and secure in place with clamp and large B nut. Torque nut 40 to 58 ft.lbs. (54.23 to 78.63 Nm). 2. Connect two sensing lines, tube, overheat temperature switch wiring and on-off wiring.
21-10.
SENSOR. REMOTE 21-10.SENSOR. REMOTE
The remote sensor (18, figure 21-2 or 21-3) is installed on top of plenum chamber. The sensor controls the mixing valve through a bleed air port. 21-11.
Removal.
1. Remove access plate on side of fuselage below cabin door edge. 2. Disconnect sensing line (17, figure 21-2 or figure 21-3) and selecting dial cable (26) from sensor (18). 3. Remove screws attaching sensor to outlet control valve (16). Remove sensor. 21-12.
21-13· 21-13.
SELECTOR. SELECTOR.
21-14.
Removal.
1. Remove access plate on underside of
fuselage to right of center line and under the outlet control valve (16, figure 21-2 or figure
2. Disconnect electrical cable and remove four mount screws on selector (15). 3.
Remove selector and small shaft adapter.
21-15.
Installation and rigging. NOTE
This rigging procedure is to be used when replacing selector (15, figure 21-2) or outlet control valve. 1. Set AFT outlet switch overhead panel to ON.
3. Remove sensor (16, figure 21-2), or cover (3, figure 21-4), as applicable. NOTE The position of flapper (1, figure 21-
Installation. MATERIALS REQUIRED
NUMBER
NOMENCLATURE
C-405
Lockwire
Position sensor in place on side of control
valve and secure with attaching screw. Secure screws with lockwire (C-405).
2. Connect pressure sensing line and selecting dial cable. 21-00-00 Page 10
on the
2. Connect selector (4, figure 21-4) to wire harness and allow selector to rotate to open position.
4) may be checked
1.
located
by looking
through opening under cover (3) with a inspection mirror. 4. Rotate flapper (1) to horizontal position.
(open)
5. Install adapter (5) on shaft (2), position as shown on view B-B, and install selector (4) on outlet control valve.
6. Turn AFT outlet switch to OFF and observe shaft (2) rotates to closed position.
BHT-212-MM
7. Turn AFT outlet switch to ON and check flapper (1) returns to horizontal (open) position.
2. Remove necessary clamps, couplings, and/or tape wrapping securing component to airframe and connecting parts.
8. Install four mount screws securing
3. Remove component through access
selector to control valve.
opening.
9. Perform operational check to ensure proper operation of cabin heater valve.
4. Cover opening to prevent entry of foreign material.
21-16.
OUTLET CONTROL VALVE.
21-17.
Removal.
2. Remove selector (15, figure 21-2 or figure 21-3), sensor (18), and connecting ducts from valve. 3. Remove valve mounting remove valve.
hardware and
1. Position valve on mounting brackets in airframe and secure in place with attaching hardware. and sensor.
3. Check for proper operation deck plate. 21-19.
Connect and install
HEAT/VENT AIR DUCTS.
The air ducts carry and selected temperature air to areas within cabin as directed by crew.
The flexible air ducts are made from silicone impregnated fiberglass cloth. The rigid ducts are made from polycarbonate material.
These are secured in airframe by clamps, brackets, and couplings. 21-20.
1.
NUMBER
NOMENCLATURE
C-306
Toluene
C-314 C-347
Adhesive Xylene
C-404
Glass Cloth
1. Repair damage which does not penetrate flexible air ducts as follows:
Installation.
2. Install selector ducts to valve.
Repair. MATERIALS REQUIRED
1. Remove cabin deck plate adjacent to right doorpost.
21-18.
21-21.
a. Repair scuffs and abrasions which do not penetrate through cloth and are not more the 3.0 in. (76.2 mm) long by 1.5 in. (38.1 mm) wide. A maximum of two repairs per 12.0 in. (20.5 cm), covering up to 10% of surface area are acceptable. b. Clean damaged area using toluene (C306) or xylene (C-347). Allow area to air dry for at least 30 minutes. c. Apply brush coat of adhesive (C-314) over damaged area with a minimum of 0.50 in. (12.7 mm) overlap beyond damage.
d.
Smooth adhesive and cure by air
drying for a minimum of two hours at room temperature or unti dry to the touch. 2. Repair damage which penetrates duct as follows:
Removal.
Remove applicable
deck plates and
access doors to provide access to component to be removed. 21-00-00 Page
11
BHT-212-MM
MATERIALS REQUIRED (CONT)
NOTE Repairs covering up to 10% of the
surface area of the duct are
NUMBER
NOMENCLATURE
C-439
Tape
acceptable. a. Clean circumference of duct damaged area with toluene (C-306) or xylene (C-347). Allow area to air dry for at least 30 minutes. b. Cut one piece of glass cloth (C-404) to cover duct circumference with at least 1.0 in. (25.4 mm) overlap of damaged area.
c.
Apply one thin smooth brush coat of
adhesive (C-314) around duct circumference in area to be covered by cloth. d. Wrap cloth around duct and smooth out. Allow area to air dry at least two hours or until dry to the touch before using or handling the duct. 21-22.
Installation. MATERIALS REQUIRED
NUMBER
NOMENCLATURE
C-300
Adhesive
C-403
Glass Cloth
21-00-00 Page 12
1.
Position component
in place within the
system. 2.
Install applicable clamps and couplings.
3.
At connecting
ends of ducts (13 and 14,
figure 21-2) apply adhesive (C-300) to soft ends and apply three complete wraps of glass cloth (C-403), two inches wide. Do not stretch last wrap. 4. Wrap insulation on duct (12) with two turns of tape (C-439). Tape edges of tape applied at preceding step together and tape end of the tape to duct.
BHT-212-MM
2. 1. 3.
Shaft Flapper Cover
A
4. Selector 5.
Adapter
VIEW
B-B
VIEW A-A
212-M-21-4
Figure 21-4. Outlet control valve
21-00-00 Page 13/14
BHT-212-MM
VENTILATION/DEFOG SYSTEM 21-23.
VENTILATION/DEFOG SYSTEM.
Ventilation/defog system delivers outside air to windshield nozzles and nozzles on sides of instrument panel. Ram air intake grills are located on cabin nose below each windshield. Each grill is connected toa plenum chamber
and ducts connect chambers to output
nozzles. Air intake volume is controlled by knobs near instrument panel nozzles. When ram air is low, outside air may be pulled in by turning on the blower which is part of the system. 21-24.
VENTILATION BLOWER.
21-25.
Removal.
2. Disconnect electrical wire to blower and remove unit. 21-26.
Installation.
1. Position blower in system flexible duct over ends of blower.
and slide
2. Install clamps and connect electrical wire to blower 3.
Perform operational check (Chapter 96).
1. Remove clamps on flexible ducts at each end of blower (33, figure 21-2) and slide ducts back clear of blower.
21-00-00 Page 15/16
