ON:
-The Pump Pressurizes the system when the Engine is running.
OFF:
-The Pump is depressurized. Power generation stops.
Fault Light Illuminates to indicate:
-Reservoir low level.
-Reservoir overheat.
-Reservoir low air pressure.
-Pump low pressure.
-Extinguishes when the ENG PUMP switch is selected OFF, except during an overheat; in which case, the light remains on as long as the overheat is present.
PUSHED:
-The RAM Air Turbine extends. The RAT extends automatically in flight with a loss of AC buses 1 and 2.
AUTO:-The Pump is energized, provided AC power is available:
-In flight.
-On the ground, provided one engine is running or the BLUE PUMP OVRD switch has been pressed.
OFF:
-The Pump is deenergized.
Fault Light Illuminates to indicate:
-Reservoir low level.
-Reservoir overheat.
-Reservoir low air pressure.
-Pump low pressure.
-Extinguishes when the BLUE ELEC PUMP switch is selected OFF, except during an overheat; in which case, the light remains on as long as the overheat is present.
AUTO
-The reversible motor pump is armed and both yellow and green electrohydraulic valves are open. The PTU runs automatically when the differential pressure between the green and yellow systems is more than 500 psi.
OFF
-Both green and yellow PTU electrohydraulic valves are energized and close. Power transfer stops.
Fault Light Illuminates amber to indicate:
-Green or yellow reservoir overheat.
-Green or yellow reservoir low air pressure.
-Green or yellow reservoir low level.
-Extinguishes when the PTU switch is selected OFF, except during an overheat; in which case, the light 19remains on as long as the overheat is present.
ON
-The Pump is energized. If electrical power is removed, the pump remains deenergized at the next electrical power application.
OFF
-The Pump is deenergized. It is automatically energized when the forward or aft cargo door lever is operated. During cargo door operation, all other yellow system users are inhibited, except for the No. 2 engine thrust reverser and the brake accumulator.
Fault Light Illuminates amber to indicate:
-Reservoir low level.
-Reservoir overheat.
-Reservoir low air pressure.
-Pump low pressure.
-Extinguishes when the YELLOW ELEC PUMP switch is selected OFF, except during an overheat; in which case, the light remains on as long as the overheat is present.
ON
-Open Crossfeed valve. ON illuminates white.
OFF
-Closes Crossfeed valve.
OPEN Light
-Illuminates green when Crossfeed valve is fully open.
ON
-Energize associated Tank Pump; fuel feeds only when center Tank Pumps' delivery pressure drops below threshold.
OFF
-Deactivate associated Tank Pump.
FAULT Light
-Illuminates amber when the delivery pressure drops. Inhibited when OFF selected.
ON:
-Activates associated Center Tank Pump. If MAN mode is selected on MODE SEL switch.
OFF:
-Deactivate associated Center Tank Pump.
FAULT Light:
-Illuminates amber when the associated Pump is operating and delivery pressure drops.
AUTO-Center Tank Pumps control is automatic:
-Pumps operate at engine start for two minutes.
-Pumps operate provided slats are retracted.
-Pumps automatically turn off five minutes after Center Tank low level is reached.
MANUAL
-Allows manual control of Center Tank Pumps with CTR TK PUMP switches.
FAULT Light
-Illuminates amber when Center Tank has more than 550 pounds of fuel and the left or right wing Tank has less than 11,000 pounds.