LOCATION AND DESCRIPTION OF MAJOR COMPONENTS (COnt)

TM 55-2840-254-23

ACCESSORY GEARBOX ASSEMBLY. Mounts on the inlet housing. Contains drive gears and

provides mounting pads for the fuel boost pump, main oil pump, fuel control,

and power turbine overspeed governor drive. Contains self-sealing chip detector

allowing inspection without loss of oil. The power turbine overspeed governor

drive is connected through a shaft and gearing to the power output shaft. All

other drives are connected through a shaft and gearing to the compressor rotor.

FUEL BOOST PUMP. Mounts on the accessory gearbox assembly. Delivers fuel from the airframe

fuel supply through the main fuel filter to the fuel control. Increases fuel

pressure slightly ensuring a positive pressure at the fuel control inlet.

MAIN OIL PUMP. Mounts on the rear of the accessory gearbox assembly. Contains three elements

within a common housing. One element supplies lubricating oil pressure. The

second element returns main scavenge oil to the integral oil tank in the inlet

housing. The third element returns No. 4 and 5 bearing scavenge oil to the oil

tank. Contains an adjustable pressure relief valve to regulate oil pressure. Also

contains check valve to keep oil from entering engine when it is not running.

DRAIN VALVE ASSEMBLIES. Located at 6-o'clock position on combustion chamber. Spring-

Ioaded open. When engine is running, internal engine pressure keeps valve closed.

When engine is stopped, internal pressure is removed and valve opens allowing

unburned fuel in the combustion chamber to be drained.

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