Installation of the Avionics Ventilation Duct Temperature Sensor

TASK 21-26-12-400-001-A
Installation of the Avionics Ventilation Duct Temperature Sensor

ZONE: 128
FIN: 26HQ

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

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE

B. Consumable Materials

REFERENCE	DESIGNATION
No specific	lockwire 0.020 in. (0.51 mm) dia

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
128	REAR AVIONIC COMPARTMENT
824

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
3	O-RINGS	AIPC 21-26-01-10-030

E. Referenced Information

REFERENCE	DESIGNATION
TASK 21-26-00-710-001-A	Operational Check of the Avionics Equipment Ventilation-System via MCDU
TASK 21-26-00-710-001-A-01	Operational Check of the Avionics Equipment Ventilation (without the CFDS)
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 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
Duct Temperature Sensor

3. Job Set-up

CAUTION: USE ONLY THE GROUND SERVICE NETWORK TO SUPPLY ELECTRICITY BECAUSE THE AVIONICS VENTILATION SYSTEM IS NOT SERVICEABLE. IF YOU ENERGIZE THE AIRCRAFT ELECTRICAL CIRCUITS WITHOUT THE VENTILATION SYSTEM YOU WILL CAUSE DAMAGE TO ELECTRICAL EQUIPMENT.

Subtask 21-26-12-860-050-A

A. Aircraft Maintenance Configuration
(1) Make sure that the ground service network is energized (Ref. AMM TASK 24-42-00-861-001).

Subtask 21-26-12-010-051-A

B. Get Access
(1) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the access door 824.
(2) Make sure that the access door 824 is open.

Subtask 21-26-12-865-067-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AIR COND/AVNCS VENT/CTL	6HQ	D06
49VU	AIR COND/AVNCS VENT/CTL	5HQ	D05
122VU	AIR COND/AVNCS/VENT/MONG	3HQ	Y17
** ON A/C NOT FOR ALL
123VU	AVNCS VENT/EXTC/FAN	2HQ	AE02
** ON A/C ALL
123VU	AVNCS VENT/BLOWER/FAN	1HQ	AD10
** ON A/C NOT FOR ALL
123VU	AVNCS VENT/EXTC/FAN	2HQ	AC04

4. Procedure
Subtask 21-26-12-420-050-A

A. Installation of the Duct Temperature Sensor
(1) Put the new AIPC 21-26-01-10-030 O-RINGS (3) in the groove of the sensor (2).
(2) Install the sensor (2) and tighten it.
(3) Safety the sensor with lockwire 0.020 in. (0.51 mm) dia.
(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) Connect the electrical connector (1).

Subtask 21-26-12-865-068-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AIR COND/AVNCS VENT/CTL	6HQ	D06
49VU	AIR COND/AVNCS VENT/CTL	5HQ	D05
122VU	AIR COND/AVNCS/VENT/MONG	3HQ	Y17
** ON A/C NOT FOR ALL
123VU	AVNCS VENT/EXTC/FAN	2HQ	AE02
** ON A/C ALL
123VU	AVNCS VENT/BLOWER/FAN	1HQ	AD10
** ON A/C NOT FOR ALL
123VU	AVNCS VENT/EXTC/FAN	2HQ	AC04

Subtask 21-26-12-710-050-A

C. Do an operational test of the avionics equipment ventilation (Ref. AMM TASK 21-26-00-710-001).

5. Close-up
Subtask 21-26-12-410-050-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 824 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).

Subtask 21-26-12-862-051-A

B. De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

[Rev.10 from 2021] 2026.04.02 06:11:02 UTC