Fuel system

Question 1

How many gallons are unusable?

Answer 1

2.4 gallons per tank for a total of 4.8 US gals

Question 2

Explain how the system alerts the pilot to low fuel conditions

Answer 2

1 hour or less of fuel remaining, based on the current fuel flow, the system provides a yellow/green cross hatch (barber pole) indication on the fuel quantity EICAS page.
The low level sensor provides an independent indication when fuel quantity goes below 215 +/- 45 pounds (98 +/- 20 KG) a yellow indication on the fuel quantity EICAS page and a Fuel 1/2 Low caution light.

Question 3

How many fuel probes are in each tank and why?

Answer 3

Two probes per tank to provide attitude compensated fuel level. Should one of the probes fail you would see changes (oscillation) in fuel quantity value due to attitude changes.

Question 4

Total fuel capacity of each tank?

Answer 4

Pressure refuel- 382 US gals per tank for a total 764 gals / 5175 lbs
Gravity refuel- 356.5 US gals per tank for a total of 713 gals / 4830 lbs

Question 5

Fuel Anti-Ice additives are required below what OAT?

Answer 5

-20º C (-4º F)

Question 6

What could cause an Eng 1 or Eng 2 Fuel Press caution light?

Answer 6

Failure of the engine driven fuel pump 2. Leak in the fuel line (draws air instead of fuel)

Question 7

Explain the function of the Fuel Prime Pump.

Answer 7

1. Prime pump provides pressurized fuel to the APU during operation 2. Prime pump provides pressurized fuel to the main engines during engine start
2. With the Fuel Prime Pump switch in the Auto position, the MDC will automatically switch from one prime pump to the other on power up cycles.
3. Prime pump 1 or 2 can be manually selected by putting the Fuel Prime pump switch to the appropriate position.

Question 8

What does the caution SOV 1 WRNG POSN mean?

Answer 8

The shutoff valve is not in the commanded position. Starter on and shutoff valve closed, starter off and the shutoff valve in the open position.

Question 9

Explain the use of the cross feed system and when it should be used.

Answer 9

Category A- Emergency Operations in flight.
Category B- Cruise flight only.
Cross feed for the first start of the day

Question 10

At what level does the Fuel Low indication illuminate and, with a Fuel 1 or 2 Low caution illuminated what attitudes should the pilot avoid?

Answer 10

215 lbs +/- 45 lbs

Caution:

When Fuel Low caution(s) are illuminated, avoid steady state pitch attitudes in excess of 10 Degrees nose up and lower than 5 degrees nose down.

Question 11

What is the maximum pressure for refueling single point?

Answer 11

55 PSIG