MD-11 Flight Crew Operations Manual
k
Fuel -
Description and Operation
Fuel.10.14
The vent outlet is located in the bottom of the left side of the stabilizer surface
without projections. The outlet is remote from the stabilizer tip and leading and
trailing edges.
Cross venting is also used in the tail tank vent system to prevent overboard fuel
spillage during aircraft maneuvers. The left side open vent is routed through the
constant section to connect with the right side open vent at a high location in the
tank. The right side open vent then is routed back through the constant section to
the vent box.
A climb vent is located forward in the constant section to provide venting when
both open vents may be covered during takeoff or climb. This vent has a float
valve to prevent fuel from entering the vent system during normal flight attitudes.
Drain valves are installed at low points in the cross vent lines so that fuel which
enters the vent lines during maneuvers returns to the tank. Since the possibility of
fuel entering the vent box exists, a return line from the vent box to the tank has
been provided. A flapper check valve prevents fuel from entering the vent box
through the return line.
A flame arrestor system similar to the wing fuel tank vent system is installed in
the vent box outlet valve.
Automatic Operation
Engine and APU Fuel Feed
The FSC supplies fuel to the engine and APU as follows:
• When the aircraft is parked fuel transfer is permitted.
• When APU start is selected, the FSC will check the status of boost pumps
in tank 2. If one or more pumps is operating it interrupts the APU start
pump. The APU starts and operates using fuel pressure from the operating
pump. If no pumps are operating, the APU will turn on its own start
pump. When the APU has started and ac power is available, the FSC will
turn on a tank 2 pump; 90 seconds later it will turn off the APU start
pump.
• During engine start, tanks 1, 2, and 3 aft pumps are turned on as each
respective ENG START switch is turned on.
• During taxi, tanks 1, 2, and 3 aft pumps are on. Fuel transfer is permitted.
Tail fuel management is inhibited.
• During takeoff, tanks 1, 2, and 3 forward and aft pumps are on. Aux
manifold fuel transfer and tail fuel management are inhibited.
• During climb tanks 1, 2, and 3 aft pumps are on. Fuel transfer and tail fuel
management are permitted.
• During cruise tanks 1, 2, and 3 aft pumps are on. Fuel transfer and tail fuel
management are permitted.
October 02, 2006
To Next Page
Loading...