Fuel System Flashcards
(O) What is the purpose of the collector tanks?
To provide positive fuel flow to the engines and to keep the Main ejectors / AC fuel pumps submerged.
(B) Name the different fuel tanks
Main tanks, collector tanks and surge tanks
(B) Where is fuel tank temperature taken?
Left side
(B) What types of fuel pumps are in each wing?
- Primary ejector pumps
- AC Pumps
- DC Pumps
- 3 Scavenge pumps
(B) What is the purpose of the Fuel ACMP?
- Back-up pump in case of a primary ejector pump
- Engine Start
- Cross-feed operations
(B) What is the purpose of the scavenge pumps?
Maintain fuel level in the collector box and keeps the ejector pumps submerged
(B) What pump(s) is used once an engine is started?
Associated primary ejector pump
(B) What is the purpose of the collector box?
- Keeps the fuel pumps submerged
- Ensures constant fuel flow to the respective engine
(B) What is the surge/vent tank?
- Collects fuel during wing-down maneuvers and returns it to the main tanks once the wings are level
- Equalizes tank pressure with atmosphere in flight and refueling
- This is accomplished through wing tank vent lines inside the tank to be expelled into the surge tanks which incorporates a high pressure relieve valve
(B) Can fuel be transferred from tank-to-tank or dumped overboard?
No, but during a cross-feed there is a slight transfer from the engine driven pump return line from the non-used side as a byproduct.
(B) What happens when the crossfeed switch is selected to LOW 1?
- Cross-feed valve opens
- Commands ACMP 2 to ON and provide fuel from the right tank to both engines
(B) What is the only way to close the engine fuel SOV?
Pull the associated engine fire extinguisher handle
What will the fuel 1(2) LO LEVEL EICAS be presented?
600 lbs. of fuel remaining in the associated tank
(I) What is the average weight of fuel density?
6.767lbs. per US GAL
(I) MAX FUEL CAPACITY?
20,935lbs.
(I) UNUSABLE QUANTITY PER TANK?
75lbs.
(I) MAX FUEL IMBALANCE?
794lbs.
(I) MIN FUEL TANK TEMP?
-40°C
(B) Can you cross-feed during T/O and Landing?
NO
(T) Which tank does normal APU take from? can you use another tank if available and how?
Right Tank
Yes - LOW 2
(O) What happens if the scavenger pumps stop working? Could you get any indication of this? And what should you consider?
- Fuel from the collector box flows out so that the fuel level equalizes.
- Yes, at 3,970lbs. you will received an EICAS WARNING Message FUEL 1 (2) LO LEVEL due to lower fuel quantity in the collector tank
- Engine flameouts due to fuel starvation if attitudes greater than 15° nose-up or down, uncoordinated maneuvers, or negative G’s
(T) How many Magnetic Level Indicators (MLI)? What is it for?
- 3 on each wing
- Provides alternate means for fuel measuring
(O) What is the DC Fuel Pump used for?
APU or Engine start, incase of no AC power
(O) What is motive flow? explain the process.
Using fuel to move fuel. Engine driven pumps provide motive flow by returning some of the fuel extracted from the collector tank into the Main Tank.
