Fuel System Flashcards
There are _____ separate wing fuel systems, _____ for each engine, that are connected by a _____________ _____system.
2, one, Valve-controlled crossfeed
What is the usable fuel capacity?
384 gallons
How many modes of operation on the fuel system is available?
3 - normal, auto crossfeed, and suction feed
Describe the modes of fuel operation:
Normal - Each engine receives fuel from corresponding fuel cells and boost pump
Auto Crossfeed - In the case of boost pump failure, boost pressure is obtained by supplying fuel to both engines through the crossfeed valve, from one boost pump. A drop in output pressure from the failed pump is sensed by a pressure switch, which then automatically pens the crossfeed valve when the pressure drops below 10psi and illuminates the low pressure annunciation. When pressure is restored, the annunciation extinguishes.
Suction - may be used for boost pump failure. It allows use of fuel from tanks on the side with the failed pump. It moves the crossfeed valve control from AUTO to CLOSED. A vacuum created by the engine driven pump draws fuel from the nacelle fuel tank. Suction feed is limited to 10 hours cumulative between engine driven pump overhauls.
What are the different fuel tanks?
Leading edge bladder-type tank (40gals), two outboard-wing panel bladder-type tanks (23 & 25 gals), one center section bladder-type tank (44gals), and the nacelle tank (61gals)
What tanks supply the center section and nacelle tanks?
The outboard wing tanks
What is fuel transferred to the nacelle tank by?
The fuel transfer pump in the low point of the center section tank
Fuel for each engine pumped directly from where?
The nacelle tank by an electric fuel boost pump
If a full load of fuel is needed, which tank do you fill first?
The nacelle tank, then the wing tank because fuel can only flow into the nacelle tank and not back into the wing tank
What does each engine have inside of the nacelle tank?
A boost pump
What is the boost pump pressure provided inside of the nacelle?
30psi
What color annunciation is associated with the boost pump and how many?
Red and 2
What does it mean when the FUEL PRESS annunciation pops up?
There is low fuel pressure on the side indicated.
When crossfeed is in AUTO, how is a boost pump failure identified?
Momentary illumination of the FUEL PRESS annunciation and fault warning flasher, then the FUEL CROSSFEED annunciation
How can you identify the failed boost pump during AUTO crossfeed?
Place crossfeed in the CLOSED position. The annunciation will pop up on the side that of the engine that is having the failure.