CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
IGNITION DISTRIBUTION SYSTEM
Igniter plug.
The igniter plug is a recessed gap igniter, which has :
-An input terminal contact,
-A shell seal.
- A retained insulator.
-An installation flange gasket.
-A spark gap.
The igniter plug operates in conjunction with the capacitor discharge-type ignition exciter.
An electrical potential is applied across the gap between the center electrode and the shell.
As the potential across the electrode and shell increases, a spark is emitted, igniting the fuel/air mixture.
The connection between the igniter plug and the ignition lead is surrounded by a shroud, which ducts the ignition lead cooling air around the igniter plug.
The depth of the spark igniter is controlled by the igniter bushing and igniter plug gasket(s). Each gasket is 0.38mm in thickness.
Before installing the spark igniter, a small amount of graphite grease should be applied to the threads that connect with the igniter bushing in the combustion case boss.
Note : Do not apply grease or any lubricant to the threads of the connector on the ignition lead as this will cause damage to the igniter and lead.
If the igniter has been removed for maintenance or repair, the white chamfered silicone seal must be replaced.
EFG
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CTC-201-177-01
EFFECTIVITY
74-00-00 Page 11
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
IGNITION SYSTEM
Power Supply
The ignition system receives its electrical power from the aircraft.
115 VAC/400 Hz is provided to systems A and B of the ECU, through 2 separate power supplies:
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System A from the A/C emergency bus.
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System B from the A/C normal bus.
Each supply is dedicated to one input, one providing power for ignition exciter No 1, and the other for ignition exciter No 2.
The A/C power supply will be automatically disconnected by the Engine Interface Unit (EIU) if :
- The master lever is selected OFF.
-In case of fire emergency procedure.
The A/C ignition power supply is failsafed to ON in case of a failed EIU.
Each ECU channel has a software-operated ignition on/off switch to operate one exciter/igniter. Each channel can control the operation of both switches.
A software monitor in each system keeps both ECU channels informed of the power supply status.
In normal automatic start, on the ground, switching occurs every other start (A-A-B-B-A-A etc…), assuming that N2 speed reaches 50%.
If the ground automatic start attempt fails, a second attempt is performed, energizing both igniters.
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