Fuel

Question 1

What are the ROUGH Fuel Quantities?

Answer 1

TOTAL - 171,200#
L/R MAIN - 43,000#
CENTER - 85,200#

Question 2

How many Fuel pumps are there?

Answer 2

7
6 AC - 2 for each tank; Center are “override”
1 DC - (Left Side; For APU)

Question 3

Where is the fuel temperature probe? Why?

Answer 3

• Left Tank.
• The Left Tank is colder, because there is only one F/HYD heat exchanger, versus two on the right side. This way, the coldest, most conservative temperature is displayed.

Question 4

When does the Center Tank Scavenge system activate?

Answer 4

• When the L/R Main Tanks are about half full.

- Moves the last 1000# remaining after the Center Pumps shut down from Center Tank to Main Tanks

Question 5

Why does the scavenge system have to remove approximately 1000# from the center tank?

Answer 5

The Center Tank Boost Override Pumps are equipped with UFIs, or an automatic power removal system, to prevent running the pumps dry.

Question 6

What does a FUEL CONFIG light indicate?

Answer 6

1. Imbalance
2. Low Fuel Quantity (2200# in either Main Tank)
3. Fuel in Center Tank with the Pumps OFF.

Question 7

Describe Fuel Quantity Indications.

Answer 7

1. The Fuel Quantity Processor uses probes in each tank to measure fuel level, and then corrects for density.
2. The FQP does two separate calculations - individual quantities, and a total quantity - and displays this information on the Fuel Quantity Panel.
3. The FMC also receives total fuel quantity information, and does yet another calculation based on FF to produce a calculated total. If there is a difference of >3000#, ==> FUEL DISAGREE.

Question 8

Describe Jettison Operations.

Answer 8

• From Center Tank only, through single manifold, out nozzles inboard of outboard aileron.
• Four total pumps (two normal, and two more dedicated jettison pumps) jettison fuel at ~2600ppm.
• UFIs inhibited, and pumps will operate continuously.
• 1. Fuel Jettison Selector ON - opens jettison tx valves, and arms pumps. 2. Opening Guards and PRESSing FUEL JETTISON NOZZLE switches opens jettison valves and activates pumps.

Question 9

Will you get a fuel disagree message during jettison operations?

Answer 9

No. The FMC discontinues calculations, and will reset to the new totalizer value when jettison is complete.

Question 10

What is NGS?

Answer 10

• Nitrogen Generation System.
• Converts bleed air into Nitrogen Enriched Air (NEA).
• Center Fuel System to reduce flammability.
• Automatic, no pilot control available.