Removal of the Ignition Unit (131-9(A))

TASK 49-41-38-000-003-A
Removal of the Ignition Unit (131-9(A))

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.

WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.

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 4M (13 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 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
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

3. Job Set-up
Subtask 49-41-38-860-055-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On panel 25VU, make sure that the APU MASTER pushbutton switch is in the OFF position, then wait for 7.5 minutes before you do the procedure.
(3) 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.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-41-38-865-061-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

Subtask 49-41-38-010-053-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 4M (13 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).
(3) Set the LIGHT control switch 11LJ to the ON position.

4. Procedure
Subtask 49-41-38-020-052-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 the low-tension electrical lead (1) from the ignition unit (3) and wait for six minutes before you continue.
(2) Disconnect the ignition lead (2) from the ignition unit (3).
(3) Put the CAP - BLANKING on each disconnected electrical connector.
(4) Remove the bolts (5), (6) and (7) and the washers (4).
(5) Remove the ignition unit (3) from the APU.

[Rev.10 from 2021] 2026.04.01 01:30:07 UTC