Oil Pump; Fuel Pump; N G Tachometer-Generator - Textron Cessna Grand Caravan Ex 208B Pilot's Operating Handbook And Faa Approved Airplane Flight Manual

SECTION 7 CESSNA
AIRPLANE AND SYSTEMS DESCRIPTION MODEL 208B 867 SHP
GARMIN G1000

OIL PUMP

Pressure oil is circulated from the integral oil tank through the engine
lubrication system by a self-contained, gear-type pressure pump
located in the lowest part of the oil tank. The oil pump is contained in a
cast housing which is bolted to the front face of the accessory
diaphram, and is driven by the accessory gear shaft. The oil pump body
incorporates a circular mounting boss to accommodate a check valve,
located in the end of the filter housing. A second mounting boss on the
pump accommodates a pressure relief valve.

FUEL PUMP

The engine-driven pump is mounted on the accessory gearbox at the 2
o'clock position. The pump is driven through a gear shaft and splined
coupling. The coupling splines are lubricated by oil mist from the
auxiliary gearbox through a hole in the gear shaft. Another splined
coupling shaft extends the drive to the fuel control unit which is bolted
to the rear face of the pump. Fuel from the oil-to-fuel heater enters the
fuel pump through a 74-micron inlet screen. Then, fuel enters the pump
gear chamber, is boosted to high pressure, and delivered to the fuel
control unit through a 10-micron pump outlet filter. A bypass valve and
cored passages in the pump casing enable unfiltered high pressure fuel
to flow from the pump gears to the fuel control unit should the outlet
filter become blocked. An internal passage originating at the mating
face with the fuel control unit returns bypass fuel from the fuel control
unit to the pump inlet downstream of the inlet screen. A pressure
regulating valve in this line serves to pressurize the pump gear
bushings.
N TACHOMETER-GENERATOR
g
The N tachometer-generator produces an electric current which is
g
used in conjunction with the gas generator% RPM indicator to indicate
gas generator RPM. The N tachometer-generator drive and mount
g
pad is located at the 5 o'clock position on the accessory gearbox and is
driven from the internal scavenger pump.
7-68 208BPHCUS-00
U.S.