Prep Questions Flashcards
Explain the sources of electrical generation and their priority
GEARB
Gen Ext APU RAT Bat
In flight, under normal operations, which generator has the higher load, and why?
Generator 1
More services attached, including the galley
What does the EMER GEN power?
AC Essential
DC Essential via Essential TR
Approximately how long does it take for the Emergency Generator to come online? What is powering the aircraft until that time? What is powered during this time- what do you expect to see in the flight deck?
8 seconds
PFD1, ISIS, EWD
Then ND1 and MCDU1
Batteries powering AC ESS by static inverter (1KVA) , DC ESS. Both SHED busses are shed.
What is the purpose of GEN 1 LINE pb on the overhead?
We can disconnect the Gen 1 from the network without turning off the generator- this feeds the fuel pumps upstream of the line connector
What speed must be maintained for the RAT?
140 kt
Extends at 100kt (if AC 1 + 2 lost)
Stalls at 100kts on newer models
What is the difference between selecting the Generator off and the IDG off?
IDG cannot be reconnected but Gen can be turned on again.
A solenoid retracts a pin, which springs some teeth into a screw on the IDG shaft which retracts the shaft from the gear. Must be physically retracted on the ground.
Generator is de-energised, IDG is physically disconnected
What is the purpose of selecting the APU MASTER SW in the smoke configuration checklist?
Allows outflow valve to be powered before we select MAN VS UP.
Connects the battery contactors (to DC Bat Bus) for 3 minutes.
Under what circumstances will the rat extend automatically?
AC 1 + AC 2 OFF, ADIRS 1 > 100kt
At what altitude can the APU be started in the EMER ELEC config and why?
Below FL250
To conserve battery power for APU starting- better chance of starting in denser air.
Not avaiable for 45 seconds after the loss of both engine generators (to stop electrical interference as Emer Gen comes online)
Under normal operations, under what altitude can the APU support both electrical load and bleed demand?
Limi for ground operation?
FL225
Elec power only above this
Ground operation upto 14,000ft
Name the sources of power for each of the hydraulic systems
Green: Gen 1
Blue: Elec / RAT
Yellow: Gen 2 / Elec
What control surfaces does the green/blue/yellow system power?
Ailerons BiG GoB
Elevators BiG BoY
Stabilisers GaY
Rudder GBY
Spoilers GYBYG (1-5 going outbound)
Slats GB
Flaps GY
WTB- BG for all except L flaps- BY
Why on the HYD page (in flight) does the green reservoir show slightly less than the other two?
Main Gear actuators are extended (full of fluid) when gear is retracted.
How are the hydraulic reservoirs pressurised, and why?
One way valves either side of the X-Bleed.
To stop bubbles forming in fluid and causing pump cavitation.
50PSI. LO PRESS @ 22PSI
Valve releases at 65PSI
Maintain press for 12 hours on ground, 3 hours after pneumatic failure in air
What is the purpose of the hydraulic priority valves?
Cut off hydraulic pressure to heavy load users in the event of low pressure. (1842 PSI)
(Gear, slats, flaps, Emer Gen all cut off)
What is the purpose of the hydraulic accumulators?
Helps to maintain constant pressure by covering transient demands during normal ops, also can provide brake pressure for 7 full applications (green).
Maintains parking pressure for at least 12 hours (yellow).
Capacity 1.1 ltr
Nitrogen 1885 PSI
Explain the purpose of the PTU
Tranfers pressure (not fluid) between G/Y systems in the event of loss of pressure.
Runs automatically when pressure 500 PSI different
Inhibited during:
Cargo door op
Single engine with park brake on or NWS pin inserted
What is the typical system pressure for the three systems? What pressure would you expect to see when the RAT is powering the blue system?
3000 PSI
2500 PSI
At what point does the system pressure indicate amber?
1450 PSI
Note- this is lower than priority valve threshold!
Of the dual hydraulic failures, which is the worst in your opinion? Why?
G+B
Alternate Law (Prot Lost)
Autothrust lost (unique to G+B)
Slats jammed, flaps slow
Flap 3
Direct law
(G+Y longer landing distance:
+200m due to no flap drag on landing)
Which of the dual hydraulic failures maintains the aircraft in normal law?
B+Y
Also stays in normal law on gravity extension
Why is the gear extended by gravity with a B+Y system failure?
To protect the rest of the green system as gear is a large consumer
What is the purpose of extending the landing gear at 200kt with the G+B failure?
Reverts to direct law sooner. Gives better pitch control, as elevator and slats are lost.
If slats are extended, the 200kt criteria will not appear on the ECAM.