OPERATIONS MANUAL

Power Plant
Ignition Control –
PW Model:
Continuous ignition switch
ON Continuous ignition operates.
Sets approach idle limit.
Each engine is equipped with a pair of
igniters, labeled as igniter 1 and igniter 2.
The ignition control on the overhead
panel controls each engine’s igniter pair.
Normally, on each engine, igniter 1 is
powered by AC bus 1, and igniter 2 by
AC bus 3.
Standby power to all igniters is provided
by the main standby bus which uses the
main battery as a backup.
Standby ignition selector (PW)
1 Ignition operates, even if auto
and continuous ignition are off;
standby power will energize
igniter 1. If auto or continuous
ignition is on, and auto is not
set to 1, normal power will
additionally energize igniter 2.
NORM Ignition operates when normal
power to any igniter is lost, even
if auto and continuous ignition
are off; if it affects igniter 2 only,
standby power will energize
igniter 2; if it affects igniter 1 or
both igniters, standby power will
energize igniter 1.
2 Ignition operates, even if auto
and continuous ignition are off;
standby power will energize
igniter 2. If auto or continuous
ignition is on, and auto is not
set to 2, normal power will
additionally energize igniter 1.
Auto ignition selector (PW)
Auto ignition operates in any of the
following cases:
• Nacelle anti-ice is on.
• Flaps are out of up.
• N2 RPM is below 50% during start.
The description below assumes the
standby ignition selector is set to NORM
and no electrical failures exist:
1 When auto or continuous
ignition operates, igniter 1 is
energized.
BOTH When auto or continuous
ignition operates, both igniters
are energized.
2 When auto or continuous
ignition operates, igniter 2 is
energized.
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