5/13/2016
vThe?JrI irepilots.com View topic - Questions on VOR
VOR operates in the VHF, transmitting a bearing signal by means of a Rotating Limacon and usesPhase Comparison to determine the radial.
The phase difference between the reference and variable signals on QDM 0500 (VAR 10°W) for a conventional VOR is: 0500 0400 230° 2200
An aircraft is flying on the true track 090o towards a VOR station located near the equator where the magnetic variation is 15oE. The variation at the aircraft position is SoE. The aircraft is on VOR radial: 255 278 262 285 900 towards VOR means on radial 2700. Variation east magnetic least. Since this is the case of VOR, variation at VOR will be considered and not aircraft, so 270 - 15 = 255.
The frequency range of a VOR receiver is: 108 to 117.95 MHz
4 An aircraft is 100 NM from a VOR facility. Assuming no error when using a deviation indicator where 1 dot = 2o deviation, how many dots deviation from the centre line of the instrument will represent the limits of the airway boundary? (Assume that the airway is 10 NM wide) 6.0 3.0 4.5 1.5 1 in 60 rule. Track Error = (Distance Off Track x 60)! Distance Along Track Airway = 10NM wide so an aircraft at the limit of the airway would be 5NM from centre line and 100NM from the VOR. So Distance Off Track = 5NM and the Distance Along Track = 100NM. TE = (5 x 60)! 100 TE = 300! 100 = 3 20 is 1 dot 10 is 1,12 dots (0.5) http://wtheai ri inepilots.corn'forumiVewtopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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vThe?JrI irepilots.com View topic - Questions on VOR
30 would be 0.5 x 3 = 1.5 dots
,1 1
When tracking a VOR radial inbound the aircraft would fly?
a constant track a great circle track a rhumb line track a constant heading
t Refer to figure. An aircraft is attempting to track 1860M on an airway defined by a VOR 80 nm away. The VOR indicates the aircraft position. With these indications the aircraft is on the
radial and
the airway.
0010 outside 1810 inside 0010 inside 1810 outside 186 course TO means radial 006. The deviation bar is deviated to the left that means we are right of radial 006. Each dot and the edge of the bulls eye (center circle) equates to a 2 degree deviation. That means we are 5 degree right of radial 006. That makes it 001. Applying the 1 in 60 rule TE = (Distance Off Track x 60)/Distance Along Track Distance Off Track = TE x 80 / 60 TE = 5 degrees (006 -001) Distance Off Track = 5 x 80 / 60 = 6.6 nm
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vThe?JrI irepilots.com View topic - Questions on VOR
For a 10 nm wide airway, lateral limit from the center of the airway will be be 5 nm. So 6.6 nm is out of the airway lateral limits.
An aircraft is on radial 120 with a magnetic heading of 3000, the track selector (OBS) reads: 330. The indications on the Course Deviation Indicator (CDI) are fly: left with FROM showing right with TO showing right with FROM showing left with TO showing Going TO the VOR with OBS 330 means radial selected is 150. This is left of radial of 120.
An aircraft is on a heading of 100 degrees (m) from a VOR. To make the VOR/ILS deviation indicator needle centralise with the TO flag showing, the following bearing should be selected on the OBS: 100 degrees 110 degrees 290 degrees 280 degrees
t The antenna polar diagram of a conventional VOR: Is always directed towards the aircraft Is like a figure of 8 Is a pencil beam Rotates at 30 revolutions per second The VOR ground station consists of a cylindrical cover containing a horizontal dipole which is spinning clockwise at a rate of 30 revolutions a second. Slots in the cylinder combined with the rotating dipole produce a limacon shaped polar diagram which also rotates at 30 revolutions a second. The ADF cardioid has a sharp null, but VOR I/macon does not. To a receiver listening to the signal the amplitude appears to go up and down 30 times a second as the I/macon rotates.
Which of the following statements concerning the variable, or directional, signal of a conventional VOR is correct? The transmitter varies the amplitude of the variable signal by 30 Hz each time it rotates The rotation of the variable signal at a rate of 30 times per second gives it the characteristics of a 30 Hz amplitude modulation The transmitter changes the frequency of the variable signal by 30 Hz either side of the allocated frequency each time it rotates The receiver adds 30 Hz to the variable signal before combining it with the reference signal
The basic principle of operation of a standard VOR is by: http://wtheai ri inepilots.corn'forumiVewtopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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phase comparison between a 108 Mhz reference signal and a 30 Hz variable signal phase difference between a frequency modulated reference signal and an amplitude modulated variable signal phase comparison between an amplitude modulated reference signal and a frequency modulated variable signal phase comparison between a 30 Hz reference signal and a 108 Mhz variable signal Just to remember (for conventional/standard VORs), "ReFerence" has an "F" so it is "F" (Frequency) Modulated. The received signal is amplitude modulated (AM) at 30 Hz. The exact phase of the AM signal differs
depending on the bearing of the aircraft from the VOR. To detect this phase difference, an omni-directional reference signal (also at 30 Hz) is also sent out by the transmitter. In order that the two 30 Hz modulations can be distinguished the reference signal is frequency
modulated (FM). The signals are arranged so that the reference signal and the variphase signal are in phase to the magnetic north of the station. Anywhere else will show a phase difference between 0 0 and 360 0 . The receiving aircraft looks at the phase difference between the FM reference signal and the AM variphase signal and displays it as a radial, a QDR. No phase difference means the receiver is on the 3600 radial. A phase difference of 1501 means it is on the 150 0 radial.
If true bearings are desired the variation at the station must be used in the conversion. This is because the radials are referenced to magnetic north at the station, rather than at the aircraft.
t3
The two signals transmitted by a conventional VOR ground station are 90o out of phase on
magnetic EAST.
S Which of the following errors is associated with the use of VOR? Scalloping Coastal refraction Quadrantal error Night effect Reflections from terrain and man made obstructions can cause errors as two signals with different phase
differences in tefere. This will cause the course deviation indicator on the VOR indicator to move rapidly from side to side - too fast for an aircraft to follow - and it will make the needle on an RMI wobble. The effect is
known as scalloping or, when reflections come from very near the beacon, site error. The unauthorised use of Passenger Electronic Devices can create a similar effect. Scalloping should be differentiated from 'beam bends' which are also caused by reflections from buildings but which are more predictable slight curves within the system tolerances. Because of its higher frequency and line of sight transmission VOR is free from sky wave interference and coastal refraction. Any bending of the signal by the structure of the aeroplane would not affect the indicated bearing so quadrantal error does not exist with VORs.
.tThe quoted accuracy of VOR is valid:
:
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At all times By day only By night only At all times except dawn and dusk
t Transmissions from VOR facilities may be adversely affected by: static interference uneven propagation over irregular ground surfaces night effect quadrantal error
The VOR system is limited to about 10 of accuracy. One degree at 200 NM represents a width of: 2.0 NM 3.5 NM 2.5 NM 3.0 NM 1 in 60 rule. Distance off track = 200/60 = 3.33 nm (3.5 the closest answer)
t;? Using a VOR outside the DOC may result in interference from: other beacons other aircraft sky waves ground waves interference from other VORs operating on the same frequency, interference from other transmitters.
:4. With reference to the VOR: Failure of the monitor will cause the beacon to cease its ident A typical VOR frequency is 118.15 Mhz The TO/FROM indicator shows whether the aircraft is heading towards or away from the beacon Wide coverage is obtained from only a few beacons VOR transmitter is monitored to make sure it puts out bearings accurate to ± 10 . If the monitor detects a greater bearing error the transmitter is shut down and a standby transmitter is brought on line. A station will also be shut down if the signal strength drops by more than 15% or if the monitor fails. During the transfer period the station ident ceases or is replaced by a continuous tone. The ident is resumed when the standby transmitter is operating within limits.
An airway 10 NM wide is to be defined by two VORs each having a resultant bearing accuracy of plus
I
or minus 5.5o. In order to ensure accurate track guidance within the airway limits the maximum http://wtheai ri inepilots.corn'forumiVewtopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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vThe?JrI irepilots.com View topic - Questions on VOR
distance apart for the transmitter is approximately: 165 NM 50 NM 105 NM 210 NM N am-fill TE = Dist Off Track/Dist Along Track x 60 5.5 = 5 / Dist Along Track x 60 Dist Along Track = 54.5 Between two VORs = 54.5 x 2 = 109 nm
An RMI slaved to a remote indicating compass has gone unserviceable and is locked on to a reading of 090o. The tail of the VOR pointer shows 135o. The available information from the VOR is: Radial 315o, relative bearing unknown Radial unknown, relative bearing 225o Radial unknown, relative bearing 045o Radial 135o, relative bearing unknown For explanation see the following links:
If the compass providing information to the RMI suddenly gets a 20o deviation: the magnetic track to the VOR station may be read on the compass card under the tip of the VOR the number of the received radial may still be read on the compass card under the tail of the VOR needle the relative bearing to the VOR, as observed on the RMI, will jump 200 all 3 answers are correct
t Refer to the diagram of a VOR/ILS deviation indicator. Assume that the indicator is set to define the centreline of an airway, that the aircraft is 90 nm from the VOR and inbound to the facility. At the time of observation the aircraft was located on radial:
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vThe?JrI irepilots.com View topic - Questions on VOR
063 253 245 243 OBS 248 with TO indication means selected radial is 068. Each dot and the edge of the bulls eye (center circle) equates to a 2 degree deviation. That means we are right of radial 068 by 5 degrees. So the aircraft is on radial 063.
t The TO/FROM indicator of a VOR: Tells whether you are now flying towards or from the VOR Tells whether a track equal to the selected bearing will bring you to or away from the VOR Tells whether the deviation indicator shows that you should manoeuvre the aircraft towards or from the CDI needle Tells whether you should turn the aircraft towards or away from the CDI indication
Using a 5 dot CDI, how many dots would show for an aircraft on the edge of an airway at 100 nm from the VOR beacon? 1.5 dots 1 in 60 rule. TE = 5/100 x 60 = 3 degrees In a S dot CDI, 1 dot is 2 degrees. So 3 degree would be 1.5 dots
An Omni-bearing selector (OBS) shows full deflection to the left when within range of a serviceable VOR. What angular deviation are you from the selected radial? 10 deg or more
& In a conventional VOR the direction of rotation of the signal will be (i) and the variable signal is (ii). In doppler VOR the reference signal is (iii) and the direction of rotation will (iv): (i) Clockwise; (U) FM; (iii) FM; (iv) Clockwise http://wtheai ri inepilots.corn'forumiVewtopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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(I) Anticlockwise; (ii) AM; (Hi) AM; (iv) Clockwise (I) Clockwise; (ii) AM; (iii) AM; (iv) Anticlockwise (i) Anticlockwise; (ii) FM; (iii) AM; (iv) Anticlockwise
1
A VOT is: "A Test VOR"
;t With reference to a VOR, the cone of confusion is: "the area directly overhead a VOR"
:* An aircraft on a heading of 270o (M) has 093 set on the CBS and TO indicated on the VOR L/R deviation indicator. The needle shows two dots fly left. The aircraft is on the: 277 radial 089 radial 097 radial 269 radial 093 set on OBS with TO indication means the aircraft intends to fly radial 273 inbound towards the VOR. Fly left indication means the aicraft is right of radial 273 (facing the VOR since the indication is To).
S You are on a compass heading of 090o on the 255 radial from a VOR. You set the course 190o on your OBS. The deviation bar will show: Full scale deflection right with a from indication Full scale deflection left with a from indication Full scale deflection left with a to indication Full scale deflection right with a to indication Give attention to the question where it says From a VOR, otherwise on radial 255 with TO indication, full scale deflection towards right is also possible and is given in the answers. Here's a tool to visualize [http://www.visi.com/—mim/nav]
Your aircraft is heading 075oM. The OBI is set to 025o. The VOR indications are TO with the needle showing right deflection. Relative to the station, you are situated in a quadrant defined by the radials: 115 and 205 295 and 025 025 and 115 205 and 295 Locate your position, draw the radials and see in which quadrant you are.
:. A frequency most suitable for a terminal VOR would be:
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vThe?JrI irepilots.com View topic - Questions on VOR
108.20 108.15 108.10 118.05 Frequencies are between 108 MHz and 117.975 MHz. Between 108 MHz and 112 MHz the band is shared with ILS so VOR frequencies are only allocated at EVEN 100 KHz spacing.
4 The Declared Operational Coverage of a VOR is: An altitude and range limited by transmitter power A range limited by transmitter power An altitude and range limited by signal to noise ratio A range limited by signal to noise ratio
: When comparing conventional and Doppler VaR, which of the following applies to the Doppler VOR: The reference and variphase signals are reversed but the phase difference remains the same The reference and variphase signals are the same but the phase difference is reversed The reference and variphase signals are reversed and the phase relationship remains the same The reference and variphase signals are reversed and the phase relationship is reversed
What are the indications to show that you are receiving a Doppler VOR: "There is no difference from the conventional VOR indications"
With regard to the monitoring of VOR, the monitor will remove the identification or switch off the VOR transmitter if there is a change of measured bearing greater than: .11 degree"
An aircraft is inbound to VOR X on the 073 radial and has a Doppler drift of 12oL. A position report is required when crossing the 133 radial from VOR Y. If the aircraft is on track the RMI indications at the reporting point will be: Heading ; 085 ; X Pointer ; 073 ; Y Pointer; 133 Heading ; 085 ; X Pointer ; 253 ; Y Pointer; 133 Heading ; 265 ; X Pointer ; 073 ; Y Pointer; 313 Heading; 265 ; X Pointer; 253 ; V Pointer; 313
3
When the term radial is used in reference to VOR it means: "The magnetic bearing from the VOR
station"
t The maximum width of the cone of silence above a VOR at 30,000 ft is: 4.1 nm 8.2 nm http://wtheai ri inepilots.com'forumi,jevAopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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vThe?JrI irepilots.com View topic - Questions on VOR
11.6 nm 5.8 nm The ICAO limits of the cone of confusion are up to 500 from the vertical. 1 in 60 rule is a rule of thumb used based on the small-angle approximation, so it will not give the correct answer. Trigonometry will have to be used: Tan of angle = opposite! adjacent adjacent = height of aircraft (30,000 feet or 4.93 nm) opposite = radius of the cone Tan of 501= Radius of the cone / 4.93 Radius of the cone = 5.87
Width of the cone = 5.87 x 2 = 11.74
tA VOR indication of 240o FROM is given. Variation at the aircraft is 9W and at the VOR is 7W. The heading 0(T) in nil wind to reach the station is: 231 051 053 233 Magnetic radial 240, with 7W variation becomes 233 True. Going towards the station on radial 233, will make the heading 053 (true).
An aircraft is maintaining an airway centreline of 0000 defined by a VOR ahead of the aircraft. Variation at the VOR is SE. At 60 nm to go the QDM is 004. The aircraft's position relative to the airway lateral boundary is:
3 nm inside the airways eastern boundary 1 nm inside the airways western boundary 1 nm outside the airways western boundary 1 nm inside the airways eastern boundary
A CDI indicates 275/TO with the needle showing 2.5 dots fly right. The aircraft is 20 nm from the beacon on a heading of 330 M. The radial that the aircraft is on and the correct way to turn after intercepting the required track to fly to the facility is: 092 right 100 left 272 right 280 left 275 TO means radial 095. Fly right 2.5 dots means left of radial 095 by S degrees which makes it 100. http://wtheai ri inepilots.corn'forumiVewtopic.php?t= 865&iew= pret4ous&sid=981 c8b882c155708843fd67039e8f63c
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vThe?JrI irepilots.com View topic - Questions on VOR
Thats enough to select the right answer. However left turn is required to decrease the intercept angle since on a heaing of 330 the intercept angle will be (330-275) 55 degrees.
t: You are homing to overhead a VORTAC and will descent from 7500 QNH to be 1000 AMSL by 6 nm DFV1E. Your ground speed is 156 knots and the ROD will be 800 fpm. At what range from the VORTAC do you commence the descent? 27.1 nm 15.8 nm 11.7 nm 30.2 nm Height to loose 7500-1000 = 6500 feet ROD = 800 fpm Time required = 6500/800 = 8.125 minutes or 0.1354 hours Distance = GS (156) x Time (0.1354) = 21.12 nm Since the level off is at 6 nm before VORTAC the distance to start descent is 21.12 + 6 = 27.1 nm
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Il/li