POWERPLANT
AIRPLANE
OPERATIONS
MANUAL
2-10-15
Page
2
Code
01
REVISION 24
LUBE AND SCAVENGE PUMP
The pressure and scavenge pumps are all mounted in a single integral
unit. A single shaft drives six pumping elements. One pressure
pumping element pumps oil from the tank to the system and five
scavenge pumping elements pump oil from the sumps and the
gearbox to the oil tank. The pump assembly also includes a pressure
regulating valve which controls oil pressure. Main Oil Pressures varies
with center sump air pressure. A line connecting one side of the
regulating valve to the center sump enables the regulating valve to
compensate for the air pressure inside the sump.
OIL FILTER UNIT
The filter unit includes a replaceable filter element, and mechanical
and electrical impending-bypass indicators. A bypass valve opens and
allows oil to bypass the filter during cold starts, or when the filter
becomes excessively contaminated. A screen is located in the bypass
inlet to prevent passage of particles. The electrical impending-bypass
indicator provides the remote monitoring of the system.
AIR-COOLED OIL COOLER (ACOC)
The ACOC is a surface-type heat exchanger with a single plate-fin oil
section. Filtered, pressurized oil enters a manifold and flows through
the air-cooled heat exchanger. A thermal/pressure bypass valve
senses ACOC outlet temperature. When open, this valve allows cold
oil to bypass the ACOC and, once closed, forces hot oil to flow through
the cooler. The bypass valve also opens if the cooler is obstructed.
FUEL-COOLED OIL COOLER (FCOC)
The FCOC is a heat exchanger that simultaneously cools the engine
lubrication oil and warms the fuel upstream of the FPMU filter. A
thermal/pressure bypass valve prevents fuel overheat. This valve also
opens in case of cooler obstruction or cold starts.
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