TM 55-1510-220-10
Figure 2-12. Overhead Control Panel
2-29. ENGINE CHIP DETECTION SYSTEM.
A magnetic chip detector is installed in the bottom
of each engine nose gearbox to warn the pilot of oil
contamination and possible engine failure. The sensor is
an electrically insulated gap immersed in the oil,
functioning as a normally open switch. If a large metal
chip or a mass of small particles bridge the detector gap,
a circuit is completed, sending a signal to illuminate a red
annunciator panel indicator light placarded No.1 CHIP
DETR or No.2 CHIP DETR and the MASTER WARNING
lights. Chip detector circuits are protected by two 5-
ampere circuit breakers, placarded No.1 CHIP DETR and
No.2 CHIP DETR on the overhead circuit breaker panel
(fig. 2-27).
2-30. ENGINE IGNITION SYSTEM.
a.
Description. The basic ignition system consists of
a solid state ignition exciter unit, two igniter plugs, two
shielded ignition cables, pilot controlled IGNITION AND
ENGINE START switches and the ENG AUTO IGN
switch. Placing an IGNITION AND ENGINE START
switch to ON (forward) will cause the respective igniter
plugs to spark, igniting the fuel/air mixture sprayed into
the combustion chamber by the fuel nozzles. The
ignition system is activated for ground and air starts, but
is switched off after combustion light up.
b.
Ignition and Engine Start Switches. Two three-
position toggle switches, placarded IGNITION AND
ENGINE START, are located on the overhead control
panel (fig. 2-12). These switches will initiate starter
motoring and ignition in the ON position, or will motor the
engine in the STARTER ONLY position. The ON switch
position completes the starter circuit for engine rotation,
energizes the igniter plugs for fuel combustion, and
activates the No.1 IGN ON or No.2 IGN ON light on the
annunciator panel. In the center position the switch is
OFF. Two 5ampere circuit breakers on the overhead
circuit breaker panel, placarded IGNITOR CONTR No.1
and No.2, protect ignition circuits. Two 5-ampere circuit
breakers on the overhead circuit breaker panel, placarded
START CONTR No.1 and No.2, protect starter control
circuits (fig. 2-27).
2-31. AUTOIGNITION SYSTEM.
If armed, the autoignition system automatically
provides combustion re-ignition of either engine should
accidental flameout occur. The system is not essential to
normal engine opera
2-26
