Hydraulics *** Flashcards
When will the demand pumps operate if the hydraulic demand pump selector is
in the AUTO position?
- EDP pump output pressure is low
- Fuel control switch is in CUTOFF
- Demand pumps 1 & 4 also operate when flaps are in transit, or flaps extended past 1
What does the hydraulic system (SYS FAULT) fault light indicate?
- Low hydraulic system pressure
- Low hydraulic reservoir quantity
- Excessive hydraulic fluid temperature
What does a hydraulic demand pump low PRESS light indicate?
- Demand pump selector positioned to OFF or AUX
* Demand pump commanded to operate and output pressure is low
What does a hydraulic reservoir quantity indication of .80 mean, as displayed on
the Secondary EICAS display?
• 80% of normal service level
What does a magenta “RF” displayed next to a hydraulic quantity indicator on
the Secondary EICAS mean?
• The reservoir requires refill
When is the engine driven hydraulic pump pressurized?
- The engine is running
* The engine pump switch is ON
Which demand pumps are air driven, and which ones are electric motor driven?
- Systems 1 and 4 are air driven pumps, through the bleed air manifold.
- Systems 2 and 3 are electric driven pumps.
What is the purpose of the auxiliary pump?
• Used for ground handling operations
- Example: Wheel Braking for towing.
Why are the hydraulic reservoirs pressurized by the bleed air system?
- To prevent pump cavitation
* To ensure positive flow during high demand conditions
If engine-driven pumps are operating normally, demand pumps 1 and 4 also operate?
- when flas are In transit on the ground.
- Flaps out of 1 in flight.
How does pulling FIRE Switch affect HYD SYS?
- EDP SOV closes
- EDP Depressurizes
- Related demand pump operates
Which HYD systems provide redundant power to primary flight controls?
SYS 1 and 4
HYD systems power primary flight controls?
SYS 2 and 3
HYD systems for upper/lower YD?
Upper - HYD SYS 3
Lower - HYD SYS 2
HYD system for stab trim and elevator feel?
HYD SYS 2 and 3
Which HYD systems power AP servos L, C, and R?
L = HYD SYS 3
C = HYD SYS 1
R = HYD SYS 2
Which HYD systems power the spoilers?
HYD SYS 2,3, and 4
Gear retraction HYD systems (numbered)?
1
4 | | 4
1
Speedbrake/Spoiler HYD systems (numbered)?
3-2-2-3 4-4 | | 4-4 3-2-2-3
Trailing Edge Flaps HYD systems (numbered)?
4-1 | | 1-4
PRESS amber light on engine pump switch?
Low engine HYD pump pressure
What happens when Demand Pump selector is placed in AUX position?
Pressurizes SYS 4 on the ground if GROUND HANDLING BUS is powered.
Aileron HYD SYS (numbered)?
(1/2)(1/3) | | (4/2)(4/3)
Nosewheel and Body Wheel Steer HYD SYS?
HYD SYS 1
Wheel Brakes HYD SYS?
NORM - SYS 4 Auto brake / anti-skid
ALT - SYS 1. No Autobarke / anti-skid
ALT - SYS 2. No Autobarke / anti-skid
Altérnate with Anti-Skid only lateral pairs of brakes front or back pair on each truck
Elevator HYD SYS (numbered)?
(1)(1/2) | | (3/4)(4)
Upper Rudder HYD SYS (numbered)?
1
3
Lower Rudder HYD SYS (numbered)?
2
4
What 4 monitors are observed when HYD SYS 4 - AUX ON?
- SYS FAULT Light OFF
- PRESS Light ON
- BRAKE SOURCE Light OFF
- ACCUMULATOR PRESS in GREEN band
What HYD SYS pressurized the BRAKE ACCUMULATOR?
HYD SYS 4
When will AUX Pump #4 stop its operation with the switch in the AUX position?
When the #4 EDHP is pressurized.
- EICAS: HYD PRESS DEM 4 displayed
With the loss of hydraulic system 4 how do I lower the landing gear and flaps?
The Landing gear will have to be lowered using the Alternate Gear Extension switch.
The flaps will revert to Secondary mode and extend more slowly.
What may cause the nose to pitch up on landing with the loss of hydraulic system 4?
Rapid extension of the Spoilers.
What are some examples of major system components powered by each hydraulic system 1 and 4
• Systems 1 and 4 power the
steering
body gear
normal brakes (SYS 4),
alternate brakes (SYS 1),
trailing edge flaps
Systems 1 and 4 also provide redundant power to the primary flight controls.
What are some examples of major system components powered by each hydraulic system 2 and 3
• Systems 2 and 3 power the
primary flight controls
stabilizer trim
elevator feel.
System 2 also powers the
alternate brakes
lower yaw damper.
System 3 powers the
upper yaw damper.
What are some examples of major system components powered by each hydraulic system 1, 2 and 3
• Systems 1, 2, and 3 power
the respective center, right, and left autopilot servos (L,C,R are powered by systems 3,1,2 respectively)
What are some examples of major system components powered by each hydraulic system 2, 3 and 4
• Systems 2, 3, and 4 power the spoilers.
What are some examples of major system components powered by each hydraulic system
System 1 and 4?
Systems 2 and 3?
Systems 1, 2, and 3?
Systems 2, 3 and 4?
• Systems 1 and 4 power the trailing edge flaps, body gear, normal brakes (SYS 4), alternate brakes (SYS 1), and steering. Systems 1 and 4 also provide redundant power to the primary flight controls.
• Systems 2 and 3 power the primary flight controls, stabilizer trim, and elevator feel. System 2 also powers the alternate brakes and lower yaw damper. System 3 powers the upper yaw damper.
• Systems 1, 2, and 3 power the respective center, right, and left autopilot servos (L,C,R are powered by systems 3,1,2 respectively)
• Systems 2, 3, and 4 power the spoilers.
