What are the ROUGH Fuel Quantities?
TOTAL - 171,200#
L/R MAIN - 43,000#
CENTER - 85,200#
How many Fuel pumps are there?
7
6 AC - 2 for each tank; Center are “override”
1 DC - (Left Side; For APU)
Where is the fuel temperature probe? Why?
- 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.
When does the Center Tank Scavenge system activate?
- 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
Why does the scavenge system have to remove approximately 1000# from the center tank?
The Center Tank Boost Override Pumps are equipped with UFIs, or an automatic power removal system, to prevent running the pumps dry.
What does a FUEL CONFIG light indicate?
- Imbalance
- Low Fuel Quantity (2200# in either Main Tank)
- Fuel in Center Tank with the Pumps OFF.
Describe Fuel Quantity Indications.
- The Fuel Quantity Processor uses probes in each tank to measure fuel level, and then corrects for density.
- The FQP does two separate calculations - individual quantities, and a total quantity - and displays this information on the Fuel Quantity Panel.
- 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.
Describe Jettison Operations.
- 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.
- 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.
Will you get a fuel disagree message during jettison operations?
No. The FMC discontinues calculations, and will reset to the new totalizer value when jettison is complete.
What is NGS?
- Nitrogen Generation System.
- Converts bleed air into Nitrogen Enriched Air (NEA).
- Center Fuel System to reduce flammability.
- Automatic, no pilot control available.
