Subtask 10.1.10 Operate Fuel Systems

Question 1

What is the purpose of a scavenge ejector?

Answer 1

Three (3) scavenge jet pumps maintain the fuel level in the collector tank, ensuring a constant flow of fuel to the engine during normal flight

Question 2

What is the primary purpose of the main ejector?

Answer 2

The primary wing fuel pump is a venturi ejector pump (jet pump) with no moving parts, and is powered by the respective engine motive flow. It is a self-sustained pump and does not require electrical power to operate

Question 3

With the knob in AUTO, when will the AC fuel pump (1) and (2) turn on?

Answer 3

AC fuel pump (1) will turn on if;
• Main ejector fails
• During engine start (assuming AC power is available)- shuts down after engine starts
• Cross feed

AC fuel pump (2) will turn on if;
• Main ejector fails
• During engine start (assuming AC power is available)- shuts down after engine starts
• Cross feed
• APU start (if AC power is available and I’m starting the APU then AC fuel pump 2 is on)

Question 4

With the knob in AUTO, when will the DC fuel pump turn on?

Answer 4

DC fuel pump will turn on when AC power or AC fuel pumps are not available.

Question 5

What does the XFEED knob do?

Answer 5

Allows fuel to be supplied to both engines from one tank. Low 1 position will supply both engines with fuel from the (R) tank, i.e., AC fuel pump (2).

Question 6

Which fuel pumps are in the main fuel tanks? How many are there?

Answer 6

The main fuel tanks have (1) main ejector, (1) wing AC electric, (3) scavenge ejectors.

The right tank has an additional (1) DC electric.

Question 7

Recite fuel limitations; Max imbalance, Max qty., min. temp., etc.

Answer 7

MAX imbalance= 794 lbs.
MAX qty = 20,935 lbs.
MIN fuel tank temp = (-37*c)

EICAS TURNS RED when:
Fuel quantity either <=660 lbs.
Combined fuel is <=1320 lbs.

EICAS TURNS AMBER when:
Fuel qty either <=1320 lbs.
Combined fuel <=2640 lbs.

Question 8

When will a FUEL IMBALANCE appear? When will it go away?

Answer 8

When the wings fuel imbalance reaches its maximum operational limit (800 lbs.) the
FUEL IMBALANCE message will appear.

It will go away when the wings fuel imbalance reduces to 100 lbs.

Question 9

In the event of dual engine failure, which fuel pump will provide fuel to relight an engine.

Answer 9

AC fuel pump 2 (assuming RAT has deployed)

DC pump can relight an engine (can’t sustain fuel flow)