Installation of the Sensing Elements

TASK 26-13-15-400-001-A
Installation of the Sensing Elements

FIN: 21WG
FIN: 22WG

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

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
314AR, 315AL, 316AR

C. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
4	0-RINGS	AIPC 26-13-15-01-010

D. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 29-14-00-614-002-A	Pressurization of the Hydraulic Reservoirs through the Ground Connector
TASK 29-14-00-614-002-A-01	Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU)
TASK 31-32-00-860-005-A	Procedure to Get Access to the SYSTEM REPORT/TEST FIRE PROT Page
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
TASK 52-41-23-010-801-A	Opening of Access Door 314AR
TASK 52-41-23-410-801-A	Closing of Access Door 314AR
Sensing Elements of the APU Fire Detector
Sensing Elements - Installation

3. Job Set-up
Subtask 26-13-15-860-050-A

A. Aircraft Maintenance Configuration
(1) Make sure that the warning notice is in position on the panel 25VU to tell persons not to start the APU.
(2) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(3) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
(4) Make sure that the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE is in position below the APU compartment.
(5) Make sure that access door 314AR is open and safetied in the open position.
(Ref. AMM TASK 52-41-23-010-801).
(6) Make sure that the APU access doors 315AL and 316AR are open (Ref. AMM TASK 52-41-00-010-001).
(7) Make sure that the LIGHT control switch 11LJ is set to the ON position.

Subtask 26-13-15-865-051-A

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	APU/FIRE AND OVHT/DET/LOOP B	2WG	L44
121VU	APU/FIRE AND OVHT/DET/LOOP A	1WG	L43
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

4. Procedure
Subtask 26-13-15-210-050-A

A. Preparation for Installation
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.

Subtask 26-13-15-420-050-A

B. Installation of the APU Fire Sensing Elements

NOTE: The installation procedure is the same for the APU fire sensing elements 21WG and 22WG.

(1) Put the sensing elements in position.

NOTE: Obey the tolerances and length compensation limits.

Sensing Elements - Installation

(2) Install the support bushes (1) in the dual clamps (3) with the split up when horizontal and rearwards when vertical.
(3) Close the dual clamps (3) and turn the screws (2) until the red marks on the screws and on the clamps are aligned.
(4) Remove the CAP-BLANKING from each electrical connector and receptacle.
(5) Make sure that all the electrical connections are clean and in the correct condition.
(6) Install the new AIPC 26-13-15-01-010 0-RINGS (4) on the pins in the responder housings.
(7) Connect the fire/overheat detector 21WG(22WG) (7) on the mounting plate (8).
(8) Install the screws (6) and the washers (5).
(9) Connect the electrical connector 21WG(22WG)-A (9).

Subtask 26-13-15-865-054-A

C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	APU/FIRE AND OVHT/DET/LOOP B	2WG	L44
121VU	APU/FIRE AND OVHT/DET/LOOP A	1WG	L43
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

Subtask 26-13-15-710-051-A

D. Operational Test of the APU Fire and Overheat Detection with the CFDS
(1) On one Multipurpose Control and Display Unit (MCDU), get the SYSTEM REPORT/TEST/FIRE PROT page (Ref. AMM TASK 31-32-00-860-005).
(2) Do this test:

ACTION	RESULT
1.On the MCDU:	On the MCDU:
push the line key adjacent to the FDU APU indication.	the FDU APU page comes into view.
push the line key adjacent to the TEST indication.	On the FDU APU page: the TEST WAIT message comes into view for 90 seconds then goes out of view, and these messages come into view (P/N given for example only): TEST OK P/N 3720 01 01 NOTE: Ignore other indications.

5. Close-up
Subtask 26-13-15-410-052-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the LIGHT control switch 11LJ to the OFF position.
(3) Close the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(4) Close access door 314AR (Ref. AMM TASK 52-41-23-410-801).
(5) Remove the access platform(s).

Subtask 26-13-15-862-050-A

B. Put the aircraft back to its initial configuration.
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(2) Pressurize the reservoirs of the hydraulic systems.
(Ref. AMM TASK 29-14-00-614-002)
(3) Remove the warning notice.

[Rev.10 from 2021] 2026.03.31 23:43:40 UTC