MD-11 Flight Crew Operations Manual
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Fuel -
Description and Operation
Fuel.10.19
Early Transfer and No Transfer of Tip Tank Fuel
The FSC will correct for early transfer or no transfer of tip tank fuel. In the case
of early transfer the FSC will turn on the transfer pump in affected tank and open
the tank fill valve. In the case of no transfer, normal lateral fuel imbalance
requirements are stopped. The FSC will alternate between the other two main
tanks using their transfer pumps and opening the fill valve of the affected tank
until the usable fuel is distributed equally. An alert, TNK 1/3 TIP TRAPPED, will
be displayed.
Equalization of Tank Quantities
The FSC will equalize tank quantities during low fuel flight. When tank 2 is below
18,824 kilograms, the FSC will correct fuel quantity imbalance between any two
main tanks that exceeds 1,089 kilograms.
The FSC will maintain wing fuel quantity balance between tanks 1 and 3.
Imbalance correction between tanks 1 and 3 stops when wing tip fuel quantity is
less than 227 kilograms or tank 2 quantity is less than 1,814 kilograms.
Fuel Tank Overfill Correction
The FSC will correct for tank overfill. For the main and auxiliary tanks, the FSC
stops transfer and depressurizes the manifold, then determines which tank is
overfilled and controls the quantity of that tank 907 to 1,361 kilograms below full.
All three main tanks are controlled at 907 to 1,361 kilograms below full for the
remainder of the flight.
Tail tank overfill correction occurs as follows: After the FSC detects the overfill
float has gone up, fuel will be transferred out until the total quantity is below 5,443
kilograms or until the overfill condition stops. The tail tank will then be limited to
a maximum of 5,443 kilograms. If the tail tank overfills twice on the same flight,
fuel will be transferred out of the tail tank until the total tail tank quantity is below
4,536 kilograms. If the tail tank overfills a third time on the same flight, tail fuel
management will be terminated and the tail tank will be emptied.
Compensation for Inoperative Components
The FSCs will reconfigure the fuel system for failure of various elements. The
FSC can compensate for a number of fuel system component failures by use of
alternate pumps and flow paths.
The FSC will turn off all transfer pumps and close the crossfeed valves if a dump
valve fails open.
The FSC will employ special management procedures to compensate for various
components being inoperative at the beginning of a flight.
November 10, 2008
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