HYDRAULICS 1. GENERAL ¡ 3 separate & independent hydraulic systems : - Left Ô powered by 1 Engine pump & 1 Electric pump - Center Ô powered by 2 Electric pumps & 1 Air Driven pump - Right Ô powered by 1 Engine pump & 1 Electric pump
If required, a Ram Air Turbine (RAT) can provide power to the flight controls portion of the Center hydraulic system (in case of double engine failure)
¡ Provide power to the : - Flaps / slats - Landing gear - Tailskid - Nose wheel steering - Brakes - Flight controls - A/P servos ¡ Center hydraulic system provide power (if both Main AC buses are lost) to the Hydraulic Driven Generator (HDG).
2. DISTRIBUTION L+C+R
L+R
L only
L+C
Ô Elevators Ô Rudder Ô Spoilers Ô Stab Trim
Ô Outboard Ailerons
Ô Rudder ratio Ô Left A/P
Ô Yaw Dampers Ô Elevator Feel Ô Left Inboard aileron
R only
R+C
Ô Right Ô Normal Inboard aileron Brakes Ô Right A/P
C only Ô Tail Skid Ô Flaps & Slats Ô Main Gear Ô Nose gear Ô Nose Wheel Steering Ô Alternate Brakes Ô 5 KVA Gen Ô Center A/P Ô RAT
3. LEFT AND RIGHT SYSTEMS ¡ Quantity and Refill on EICAS Status display ¡ Independent reservoirs fluid pressurized by bleed air to ensure positive fluid flow. ¡ Each reservoir has a LOW QTY light ¡ Fluid flows through Shutoff valves (SOV) controlled by L & R Engine Fire switches Pulling Fire switch Ô closes the SOV Ô depressurizes the pump ¡ Engine pump = primary power ¡ Electric Demand Pump : Ô in AUTO - starts when pressure is low - Low Pressure only with pump signaled to operate. Ô LEFT inhibited on ground during engine start with only 1 generator (low pressure lights may illuminate)
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
Page 2
4. CENTER SYSTEM ¡ Quantity and refill on EICAS ¡ CENTER system has an independent reservoir pressurized by Bleed air to ensure positive fluid flow ¡ The reservoir has a LOW QTY light and a Standpipe to maintain a minimum level for operation of : BRAKES & STEERING in the event of a Center system hydraulic leak. ¡ Electric pumps = primary power ¡ N°2 electric pump inhibited with: Ô Only 1 generator operating Ô Both CENTER electric pump switches ON Ô LEFT and RIGHT demand pumps operating ¡ 2 Reserve brake and Steering control valves are automatically activated to allow a reserve volume of hydraulic fluid to be supplied to the CENTER N°1 Electric hydraulic pump : Ô aircraft inflight + CENTER hydraulics quantity level Low Ô SUPPLY valve opens to supply the N°1 pump Ô ISOLATION valve closes Ô ISLN light illuminates to indicate the isolation of the CENTER system. Ô A with failure of the auto system : - RESERVE BKS & STRG ON = pump operates regardless of pump switch position. - VALVE light ON and switch OFF = disagreement with auto isolation feature. switch ON = disagreement with manual selection. ¡
Air demand pump - CENTER system has a bleed air driven hydraulic pump (from the CENTER manifold) which provides hydraulic power when pressure is low or in case of large demand systems (gear, flaps, ground spoilers) - Air Demand Pump selector determines the pump mode of operation : Ô AUTO : the air pump operates when pressure is low or in case of large demand systems (gear, flaps, ground spoilers) Ô ON: the pump runs continuously - LOW pump pressure & Air demand pump OVERHEAT are provided. - Hydraulic Driven Generator (HDG) is automatically powered by the CENTER hydraulic system with loss of Main AC busses (in this case, the CENTER Air Demand Pump will operate continuously to ensure sufficient sufficient hydraulic pressure to drive the generator (A Extension time for Flaps and Slats is increased).
¡
Ram Air Turbine (RAT) Ô Located on the body fairing aft of the RIGHT main gear Ô Auto deploy with both engines failure & can only be retracted on the ground. Ô Speed should be > 130 kt for adequate power to the flight controls Ô Ram Air Turbine Pressure light (green) indicates the RAT is providing hydraulic power. Ô UNLKD light (amber) indicates the RAT not locked in the stowed position Ô Manual extension possible through the guarded RAT switch.
5.
PITCH ENHANCEMENT SYSTEM (PES)
¡ With Left and Center hydraulic systems INOP for the TRIM, Right system operates the PES using the fluid of the Left system. (see “FLIGHT CONTROLS”)
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Smartcockpit.com
6.
Page 3
BOEING 767 SYSTEMS REVIEW
FAULTS
SYSTEMS
SYSTEM CONDITION CHART (SINGLE SYSTEM FAILURE) L C R L C R L
AUTOPILOT STAB TRIM FLAPS LANDING GEAR AUTOBRAKES BRAKES THRUST REVERSERS SPOILER CAPABILITY NOSEWHEEL STEERING YAW DAMPER AILERONS RUDDER RATIO CHANGER HMG RAT
SYSTEMS
LEFT INOP HALF RATE NORMAL NORMAL NORMAL NORMAL BRAKES LEFT INOP REDUCED NORMAL RIGHT INOP NORMAL INOP NORMAL NORMAL
CENTER & RIGHT INOP HALF RATE USE ALT FLAP EXT USE ALT GEAR EXT NORMAL NORMAL BRAKES NORMAL REDUCED * LEFT INOP NORMAL NORMAL INOP INOP
CENTER & RIGHT INOP HALF RATE NORMAL USE ALT FLAP EXT USE ALT GEAR EXT INOP * LEFT ONLY REDUCED * CAPABILITY REDUCED RIGHT INBD REDUCED INOP INOP INOP
LEFT & RIGHT INOP HALF RATE NORMAL NORMAL NORMAL INOP ALT BRAKES INOP REDUCED NORMAL CAPABILITY REDUCED OUTBOARD INOP NORMAL NORMAL NORMAL
* May be available from Reserve Brake & Steering system. SYS PRESS
(amber) : Low system pressure
QTY
(amber) : Low reservoir quantity
1-ELEC-2 ON
= ON (alternate action) : Pump ON
PRESS
Copyright Smartcockpit.com Ludovic ANDRE / version 00
R
RIGHT INOP NORMAL NORMAL NORMAL INOP ALT BRAKES RIGHT INOP REDUCED NORMAL LEFT INOP NORMAL NORMAL NORMAL NORMAL
SYSTEM CONDITION CHART (DUAL SYSTEM FAILURE) L C R L C R L
AUTOPILOT STAB TRIM ELEV FEEL FLAPS LANDING GEAR AUTOBRAKES BRAKES THRUST REVERSERS SPOILER CAPABILITY NOSEWHEEL STEERING YAW DAMPER AILERONS RUDDER RATIO CHANGER HMG RAT
C
C
R
INOP ¼ RATE SPRING FEEL USE ALT FLAP EXT USE ALT GEAR EXT NORMAL NORMAL RIGHT ONLY REDUCED * INOP LEFT INBD INOP INOP INOP INOP
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
Page 4
L/R ENG ON
- ON (alternate action) : Pump pressurizes system when engine rotates - PRESS (amber) : Primary Low pump pressure
PRESS
(amber) : Primary pump is overheated.
OVHT
ELEC (amber)
PRESS OVHT
- Selector positioned to OFF, Demand Pump press is Low - Selector positioned to AUTO, Demand pump press is Low when signaled to operate - Selector positioned to ON, Demand pump press is Low
(amber) : Demand pump is overheated.
RAM AIR TURB - PUSH (alternate action) : deploys RAT - PRESS (green) : RAT deployed and producing hydraulic pressure - UNLKD (amber) : RAT unlocked.
PRESS UNLKD
Center Instrument Panel RESERVE BKS & STRG ON
VALVE
- ON (alternate action) : provides pressure to alternate brake system and nose wheel strg - VALVE (amber) : Ô switch OFF = reserve brakes & steering control valve(s) disagree with signaled position from automatic isolation feature Ô switch ON = reserve brakes & steering control valve(s) disagree with manually selected switch position.
Accessory Panel ISLN
(white) : N°1 hydraulic pump on the Center hydraulic system is isolated to provide hydraulic pressure to the Reserve brakes & Nose wheel steering system.
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
HYDRAULICS SYSTEM
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Page 5
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
HYDRAULICS DIAGRAM
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Page 6
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
LEFT HYDRAULICS LOGIC
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Page 7
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
CENTER HYDRAULICS DIAGRAM
Copyright Smartcockpit.com Ludovic ANDRE / version 00
Page 8
Smartcockpit.com
BOEING 767 SYSTEMS REVIEW
RAM AIR TURBINE (RAT)
Copyright Smartcockpit.com Ludovic ANDRE / version 00
