WA Year Two Systems study. Flashcards
The electric hydraulic pumps are AC or DC?
AC
Which hydraulic pumps supply the highest volume of hydraulic fluid, electric or engine?
Electric (about four times as much)
Where are the hydraulic fluid heat exchangers located?
Respective main fuel tanks.
Minimum fuel in a main tank for operation of an electric hydraulic pump?
760kgs
If a leak develops in the system A engine driven pump or its related lines, what will happen?
A standpipe in the reservoir prevents a total system fluid loss. With fluid level at the top of the standpipe, the reservoir quantity displayed indicates approximately 22% full (EIS) or 1/4 full (conventional). System A hydraulic pressure is maintained by the electric motor–driven pump
If a leak develops in the system A electric driven pump or its related lines, what will happen?
If a leak develops in the electric motor–driven pump or its related lines, or components common to both the engine and electric motor–driven pumps, the quantity in the reservoir steadily decreases to zero and all system pressure is lost.
If a leak develops in the system B engine driven pump or its related lines, what will happen?
If a leak develops in the engine–driven pump or its associated lines, the system B quantity decreases until it indicates approximately 40% full (EIS) 1/2 full (conventional). System pressure is maintained by the electric motor–driven pump.
If a leak develops in the system B electric driven pump or its related lines, what will happen?
If a leak develops in the electric motor–driven pump or its associated lines, system B pressure is lost. However, fluid remaining in the system B reservoir is sufficient for power transfer unit operation.
What is the purpose of the Power Transfer Unit?
To supply the additional volume of hydraulic fluid needed to operate the auto slats and leading edge flaps and slats when system B engine-driven hydraulic pump volume is lost.
It uses system A pressure to power a hydraulic motor pump, which pressurises system B hydraulic fluid.
Simplified: If you get an engine failure of no2, you can still operate the leading edge devices.
When does the Power Transfer unit operate?
When all of the following conditions are met:
- aircraft is airborne
- system B engine driven pump pressure below limits
- flaps are less than 15 but not up
What is the purpose of the Landing Gear Transfer Unit?
To supply pressurised hydraulic fluid needed to raise the landing gear at the normal rate when system A is lost due to No. 1 engine RPM loss. System B provides pressurised hydraulic fluid.
What conditions are required of the Landing Gear Transfer Unit to operate?
- aircraft is airborne
- No.1 engine drops below a limit value
- LANDING GEAR lever is positioned UP
- either main landing gear is not up and locked
The Standby Hydraulic System uses an electric motor to power which components?
- Thrust reversers
- Rudder
- Leading edge flaps and slats (extend only)
What happens when you position either FLT CONTROL switch to STBY RUD?
- activates the standby electric motor–driven pump
- shuts off the related hydraulic system pressure to ailerons, elevators and rudder by closing the flight control shutoff valve
- opens the standby rudder shutoff valve
- deactivates the related flight control LOW PRESSURE light when the standby rudder shutoff valve opens
- allows the standby system to power the rudder and thrust reversers.
- illuminates the STBY RUD ON, Master Caution, and Flight Controls (FLT CONT) lights.
Simplified: It allows standby system to power the rudder.
What happens when you position the ALTERNATE FLAPS switch to ARM?
- activates the standby electric motor–driven pump
- closes the trailing edge flap bypass valve
- arms the ALTERNATE FLAPS position switch
- allows the standby system to power the leading edge flaps and slats and thrust reversers.
Simplified: allows TE flaps to be electrically operated and allows LE devices to be operated by standby system.
What conditions are required for automatic operation of the standby Hydraulic system?
- Loss of System A or B ,
or rudder pressure reducer system fails in low pressure mode, and - TE Flaps extended, and
- Airborne or wheel speed >60kts, and
- FLT CONTROL switch A or B Hyd system ON.
OR - Main PCU Force Fight Monitor trips.
When the standby system is automatically turned on, what indications can you expect to see?
STBY RUD ON light
Master Caution - FLT CONT
What happens in case of a standby hydraulic system leak?
Standby reservoir quantity reduces to zero.
LOW QUANTITY light illuminates when reservoir is approximately half empty.
System B continues to operate normally, but system B reservoir quantity reduces to approximately 64% full (EIS) or between 1/2 and RFL (conventional)
When is the FEEL DIFF PRESS LIGHT armed?
When the trailing edge flaps are up (not on NG)
What does the FEEL DIFF PRESS light tell you?
Excessive differential pressure in elevator feel computer
What does SPEED TRIM FAIL light tell you?
indicates failure of the speed trim system
indicates failure of a single FCC channel when MASTER CAUTION
light recall is activated and light extinguishes when master caution system is reset.
What does MACH TRIM FAIL light tell you?
indicates failure of the Mach trim system
indicates failure of a single FCC channel when MASTER CAUTION
light recall is activated and light extinguishes when master caution system is reset.
What is the purpose of the speed trim system?
Improves flight characteristics during low speed flight with low gross weight, aft CG and engine RPM above 60% N1
What does the stabilizer trim override switch do?
OVERRIDE – bypasses the control column actuated stabilizer trim cutout switches to restore power to the stabilizer trim switches
During takeoff, at what speed does the rudder become aerodynamically effective?
40 - 60 kts
Why should you not use aileron trim with the autopilot engaged?
If aileron trim is used with the autopilot engaged, the trim is not reflected in the control wheel position. The autopilot overpowers the trim and holds the control wheel where it is required for heading/track control. Any aileron trim applied when the autopilot is engaged can result in an out of trim condition and an abrupt rolling movement when the autopilot is disconnected.