Engine System Flashcards
What part of the engine drives the external gearbox?
The HP shaft.
What does the engine external gearbox drive?
No. 1 and No.2 hydraulic systems. Main AC Generator. Combined LP and HP fuel pump. Oil Pump. Generator for the HP compressor and RPM tachometer. The EEC generator.
What is the normal ground idle value?
About 53% NH
What is the normal flight idle value?
56.2% NH
What busbar does the engine ignition system get its electrical power from?
The 28V DC ESB.
How many stages does the LP compressor have?
2 stages.
How many stages does the HP compressor have?
5 stages.
How many turbines are there?
2: the LP and HP turbines, each are single stage.
Where is the engine bleed valve located?
In the HP compressor case.
Why does the engine have a bleed valve?
To relieve pressure to prevent HP compressor from stalling during engine start.
What value of NH does the engine bleed valve close at during start?
Approx. 51% (2% below ground idle).
How many oil return scavenge pumps are there?
3
How is the engine oil cooled?
Using a Fuel Cooled Oil Cooler (FCOC).
How many magnetic chip detectors does the engine oil system have?
3
Where are the engine oil magnetic chip detectors located?
In the return lines (back to the reservoir).
When is the 10 second delay applied to the OIL caption (i.e. oil px warning)?
Why is this the case?
When the gear is locked up.
To prevent nuisance transient warnings.
What is used to cool the EEC circuits?
A small recirculation flow of fuel.
State the fuel flow chain between the LP fuel pump and the fuel manifold.
LP Fuel Pump FCOC LP Fuel Pump Filter HP Fuel Pump FMU/ FMV Fuel Manifold.
How is the EEC powered?
Engine below 40%NH: Powered by 28V ESB.
Engine above 40%NH: Powered by a dedicated engine driven generator.
How long are the igniters activated for when:
1) Relight button pressed on the ground (WoW).
2) FADEC/ EEC activates igniters (in automatic response to a surge).
3) Relight button pressed when airborne.
1) For as long as the button is held.
2) 15 seconds.
3) 30 seconds/ until throttle advanced past idle.
State the auto-surge-recovery process controlled by the FADEC/ EEC.
Surge detected.
Igniters energised (15s).
Waits 0.5s (to allow it to self clear).
Observes for a further 1s to see if stall/ surge occurring.
If surge detected, SRG caption illuminated for 5s (+surge audio).
EEC dips amount of fuel to engine to clear surge.
GET THIS CHECKED
Up to what NH does the air starter motor provide assistance?
45%