MD-11 Flight Crew Operations Manual
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Fuel -
Description and Operation
Fuel.10.17
• Tail fuel management can be reset by selecting manual mode, then
reselecting auto mode. If the conditions that caused termination of tail
fuel management no longer exist, management will resume.
• Cold fuel is recirculated (see following).
Cold Fuel Recirculation
Fuel temperature is maintained above freezing. Phase one involves tanks 1 and 3
and applies when fuel quantity in each main tank is greater than 6,214 kilograms.
When the fuel temperature sensed in the tank 3 tip falls to within 6°C of the fuel
freeze point, tanks 1 and 3 transfer pumps will be turned on and their fill valves
will open. An alert, COLD FUEL RECIRC will be displayed. The transfer will
continue until fuel temperature rises 5°C, or for 15 minutes. Should the tail and/or
wing fuel temperature drop within 3°C of the freeze value, an alert FUEL TEMP
LO will be displayed. Phase two involves the tail tank. When the temperature
sensed in the tail tank falls to within 8°C of the fuel freeze point, the fuel within
the tail tank is recirculated in order to raise the temperature. If the fuel temperature
drops to within 5°C of the fuel freeze point, about one third of the tail fuel is
transferred forward. It is then replaced with warmer fuel from another tank. If the
fuel temperature drops to within 3°C of the fuel freeze point, tail fuel management
is terminated.
Fuel Manifold Draining
When the fuel quantity in tank 2 drops to less than about 816 kilograms, the
manifold drain float valve in tank 2 will open to drain the fuel manifold into tank
2. The manifold drain float valve is not dependent on system operation, auto or
manual. If the fuel system is in auto the FSC will open the manifold
drain/outboard fill valves in tanks 1 and 3 when the fuel quantity in tank 2 is less
than 680 kilograms. This will allow air into the fuel manifold. If the fuel system
is in manual the manifold drain/outboard fill valves will open when the MANF
DRAIN switch is pushed. The FUEL MANF DRAIN alert will be displayed in
auto or manual when the manifold drain/outboard fill valves are open.
Preflight Checks
The FSC will perform preflight checks. The preflight test can be initiated by
maintenance. The preflight tests consist of both standard and conditional tests.
The following functions are performed:
• The standard test will:
1. Record fuel float faults from refueling.
2. Verify manifold pressure sensor operation.
3. Verify fuel dump valves closed.
4. Verify all main tank pumps are operational and supplying at least 15 psi fuel
pressure.
5. Verify crossfeed valve operation.
November 10, 2008
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