TM 55-1510-221-10
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. T wo
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 posi-
tion. 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
5-ampere 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. 2-26).
2-30. 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 operation, but is used to
reduce the possibility of power loss due to icing or
other conditions. Each engine has a separate
autoignition control switch and a green indicator
light placarded No. 1 IGN ON or No. 2 IGN ON, on
the annunciator panel. Autoignition is accomplished
by energizing the two igniter plugs in each engine.
NOTE
The system should be turned OFF during
extended ground operation to prolong the
life of the igniter plugs.
a. Autoignition Switches. Two switches,
located on the overhead control panel (fig. 2-12)
placarded ENG AUTO IGN-ARM control the
autoignition systems. The ARM position initiates a
readiness mode for the autoignition system of the
corresponding engine. The OFF position disarms the
system. Each switch is protected by a corresponding
START CONTR No. 1 or No. 2 5-ampere circuit
breaker on the overhead circuit breaker panel (fig.
2-26).
b. Autoignition Lights. If an armed autoigni-
tion system changes from a ready condition to an
operating condition (energizing the igniter plugs in
the engine) a corresponding green annunciator panel
light will illuminate. The annunciator panel light is
placarded No. 1 IGN ON or No. 2 IGN ON and indi-
Figure 2-12. Overhead Control Panel
2-26
