Hydraulic System Flashcards
What side of the aircraft and part of the wing does each hyd system work along?
Hyd 1: RHS of aircraft, leading edges of wings.
Hyd 2: LHS of aircraft, rear wing spars.
List the things that the Hyd 1 and Hyd 2 systems power.
Hyd 1: Tailplane, aileron and rudder PFCUs. Landing Gear NWS Flaps Airbrake Wheelbrakes Anti-skid Q-feel system
Hyd 2:
Tailplane and aileron PFCUs
What is the purpose of an accumulator in each hyd system?
To give short term redundancy in case of a sudden hyd failure.
To damp out any fluctuations in provided pressure and provide an instantaneous to hyd demands.
Below what Hyd 2 pressure does the RAT deploy?
1500+-100psi
Below what pressure does the PMV valve operate in the Hyd 1 system?
What is the purpose of the PMV.
1500+-100psi
The purpose of the Pressure Maintaining Valve is to prioritise powering the PFCUs over other parts of the hyd 1 system in case of a fall in hyd pressure.
What pressure does the Gear standby lowering system provide?
3300psi
What pressure does the Flap standby lowering system provide for?
3000psi.
What pressure is the RAT regulated to provide?
What regulates this?
It will cycle between 2400 and 3000psi.
A cut-out valve.
What engine RPM and Hyd 2 EDP pressure is required for Hyd 2 system to be reset and the RAT retracted?
76% RPM
2000psi.
What position do the flaps need to be in during the walkaround?
Down
What hyd pressure do the hyd systems provide when working normally?
3000psi
Where is the Hyd 1 flying controls accumulator pressure gauge located?
What pressure should it read on the walkaround?
In the right undercarriage bay.
1100psi.
Where is the wheelbrake accumulator pressure gauge located?
What pressure should it read on the walkaround?
In the right undercarriage bay/
1250psi.
Where is the Hyd 2 flying controls accumulator pressure gauge located?
What pressure should it read on the walkaround?
In the left undercarriage bay.
1100psi.
Where are the landing gear and flap standby system pressure gauges located?
What should they read on the walkaround?
In the left undercarriage bay.
Gear: 3300psi
Flap: 3000psi
What is the purpose of the wheelbrake accumulator?
To maintain pressure for the wheelbrakes so you can still apply brakes on landing.
What pressure does the wheelbrake accumulator maintain once charged by Hyd 1 system?
What is the accumulator base pressure (i.e. the pressure that should be shown on the dial in the undercarriage bay on walkaround)?
3000psi
1250psi.
If Hyd 1 has failed and you are relying on the wheelbrake accumulator for braking force, how must you brake?
In a single steady application.
Do not apply on and off again and again - you will find yourself without brakes.
How many hydraulic jacks operate the flaps?
Why?
1
To minimize the chance of asymmetric flaps.
State the number of jacks used in the landing gear system, and what each of them move.
5 jacks.
R main wheel. L main wheel. R main door. L main door. Nose gear.
What would happen if you were to fully apply the foot brakes and parking brake?
You will damage valves in the wheelbrake system.
What wheelbrake accumulator pressure will give you a boxed S?
2755 - 3150psi
What wheelbrake accumulator pressure will give you an unboxed S?
1250-2755psi
Below what wheelbrake accumulator pressure will give you a flashing unboxed S?
What implications does this have?
Below 1250psi
You have no brake pressure available to use.
