Removal of the Ignition Unit (APS 3200)

TASK 49-41-38-000-002-A
Removal of the Ignition Unit (APS 3200)

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

WARNING: MAKE SURE THAT THE IGNITION UNIT IS DE-ENERGIZED AND GROUNDED BEFORE YOU DISCONNECT THE INPUT AND OUTPUT LEADS. DO NOT TOUCH THE CONTACTS OF THE OUTPUT TERMINAL. THE OUTPUT VOLTAGE FROM THE IGNITION UNIT IS HIGH AND DOES NOT DECREASE IMMEDIATELY AFTER DE-ENERGIZATION (THE UNIT IS OF THE CAPACITOR DISCHARGE TYPE). HIGH VOLTAGE CAN KILL YOU.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 52-41-00-010-001-A	Open the APU Doors for Access
Ignition Unit (APS 3200)

3. Job Set-up
Subtask 49-41-38-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) On panel 25VU, make sure that the APU MASTER SW pushbutton switch is in the OFF position, then wait for 7.5 minutes before you do the procedure.
(2) Put a WARNING NOTICE(S) in position in the cockpit to tell persons not to push the APU MASTER SW pushbutton switch to the ON position.
(3) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-41-38-865-055-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38
121VU	APU/FIRE/LP VALVE/NORM	4WF	M42
121VU	APU/FIRE/LP VALVE/STBY	3WF	M41
121VU	APU/FUEL/LP VALVE/CTL	1QF	M40

Subtask 49-41-38-010-052-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below APU access doors 315AL and 316AR.
(2) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).

4. Procedure
Subtask 49-41-38-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the Ignition Unit

WARNING: DISCONNECT THE LOW-TENSION ELECTRICAL SUPPLY 6 MINUTES BEFORE YOU START WORK ON THE IGNITION SYSTEM. THE HIGH CURRENT AND VOLTAGE WHICH ARE USED IN THE IGNITION SYSTEM CAN KILL YOU.

(1) Disconnect electrical connector P10 (4) from the ignition unit (3) and wait for six minutes before you continue.
(2) Disconnect the igniter cables (2) from the ignition unit (3).
(3) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(4) Loosen the bolts (1), but do not remove them.
(5) Remove the ignition unit (3).

[Rev.10 from 2021] 2026.04.01 12:42:35 UTC