Engine and APU Flashcards
During APU start, when does the ON light in the START pushbutton extinguish and the AVAIL light illuminate?
Above 95% N speed. There is not an N1 indication for the APU. N is an RPM.
When you shut down the APU, will it shut down immediately?
It may run up to two minutes for cooling
Under what conditions would the APU fuel pump provide fuel pressure to the APU?
Operation is automatic if there is no pressure from another source.
the FADEC (full authority digital engine control) has full authority over the operation of the engines. During a normal engine start, when does the FADEC become powered?
The FADEC is powered once the ENG MODE selector is positioned to IGN/START.
Where does the electrical power for the FADEC come from when you first select IGN/START?
From the aircraft electrical system.
Does the FADEC always get its power from the aircrafts electrical system?
NO. When N2 increases above 15%, FADEC is powered by its own magnetic alternator.
During engine start, what will FADEC do for you if some kind of a start malfunction occurs?
With less than 50% N2, the FADEC monitors engine start parameters and, if necessary, will abort the start and auto crank the engine.
How is A/THR armed on the ground during takeoff?
By setting the thrust levers to TOGA if at least one flight director on, or by setting the thrust levers to FLEX/MCT if at least one flight director is on and a FLEX temperature has been entered in the MCDU.
Where is the engagement range?
Both thrust levers above idle (3 degree lever angle above idle) but not above the CL detent.
If I pull the thrust levers aft of the CL detent and place them in a position above idle, will the A/THR still be engaged?
Yes
What have I done to the thrust If I pull the thrust levers aft of the CL detent and place them in a position above idle?
I have set an upper limit for the thrust at that thrust lever position.
With the thrust levers in the CL detent, what would happen to the thrust if I disconnected the A/THR?
Thrust would go up to CL power (the white donut.)
The FADEC can operate in either the normal EPR mode or the alternate N1 mode. Will the A/THR work if f you are operating in the alternate N1 mode?
NO… A/THR function, including alpha floor are lost.
What would happen if you push and hold the A/THR disconnect button?
Initially, the A/THR would disconnect. Then, if held for more than 15 seconds, the A/THR system would be disconnected for the remainder of the flight, including alpha floor protection.
