**ON A/C ALL
FUEL TEMPERATURE INDICATING − DESCRIPTION AND OPERATION
1.
General
Refer to Figure 1.
The fuel temperature indicating system for the fuel feed systems of both engines consists of
temperature transmitter for each engine connected by electrical wiring to a dual indicator
which serves both engines.
2.
Description and Operation
A.
Fuel Temperature Transmitter
A fuel temperature transmitter is located in an engine supplied tapping upstream of the
engine driven pump (see ENGINE FUEL AND CONTROL − GENERAL, Figure 1). The
transmitter is a standard electrical resistance type component, in which resistance varies
in direct proportion to sensed temperature.
B.
Fuel Temperature Dual Indicator
The fuel temperature indicator for both engines is mounted on the engine instrument
panel in the flight compartment.
The indicator contains separate circuits and indicating mechanisms for engine No. 1 and
engine No. 2, which receive separate inputs from the associated transmitter. The circuits
are separately powered from the 28V dc buses and protected by 5−ampere FUEL TEMP
ENG 1 (N4) left secondary bus and FUEL TEMP ENG 2 (E4) right secondary bus, circuit
breakers. Lighting for the indicator is from the 5V dc lighting system (refer to Chapter
33).
The indicator provides a readout of fuel temperature by means of moving pointers
against a fixed dial. The pointers for engines No. 1 and No. 2 are mounted on concentric
shafts and identified 1 and 2 by a marking on the dial for each half scale.
The indicator dial is marked FUEL TEMP with the two separate half scales marked
degrees C and graduated from −40 to +80 degrees, with major graduations increments
of 40 degrees and minor graduations in increments of 10 degrees.
On Pre Mod 8/0861 aircraft the scale is provided with a green arc from +11 to +43
degrees with a red limit mark at 57 degrees, and yellow arcs +43 to +57 degrees and
−40 to +11 degrees.
On Mod 8/0861 aircraft, the scale is provided with a green arc from +11 degrees to +57
degrees, yellow arc from −40 degrees to +11 degrees and red limit mark at 57 degrees.
In the event of indicator power supply failure, the pointer(s) of the affected circuit(s)
move off scale below −40 degrees.
D
SERIES 100
AIRCRAFT MAINTENANCE MANUAL
MASTER
EFFECTIVITY: See Pageblock 73−33−00 page 1
73−33−00
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Dec 20/2004