Installation of the Avionics Ventilation Fans Speed Controller

TASK 21-26-35-400-001-A
Installation of the Avionics Ventilation Fans Speed Controller

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.

ZONE: 126
FIN: 31HQ ** ON A/C NOT FOR ALL

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. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
126	LATERAL AVIONIC COMPARTMENT
822

C. 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
Avionics Ventilation Fans Speed Controller

3. Job Set-up
Subtask 21-26-35-860-050-A ** ON A/C NOT FOR ALL

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

Subtask 21-26-35-010-051-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the access door 822.
(2) Make sure that the access door 822 is open.

Subtask 21-26-35-865-051-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR 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
123VU	AVNCS VENT/BLOWER/FAN	1HQ	AD10
123VU	AVNCS VENT/EXTC/FAN	2HQ	AE02

4. Procedure
Subtask 21-26-35-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Fans Speed Controller

Avionics Ventilation Fans Speed Controller ** ON A/C NOT FOR ALL

(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Put the controller (1) in position.
(4) Install the washers (3) and the nuts (4).
(5) Tighten the nuts (4).
(6) Remove the CAP-BLANKING from each electrical connector and receptacle.
(7) Make sure that all the electrical connections are clean and in the correct condition.
(8) Connect the electrical connectors (2) to the controller (1).

Subtask 21-26-35-865-052-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR 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
123VU	AVNCS VENT/BLOWER/FAN	1HQ	AD10
123VU	AVNCS VENT/EXTC/FAN	2HQ	AE02

Subtask 21-26-35-710-050-A ** ON A/C NOT FOR ALL

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

5. Close-up
Subtask 21-26-35-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 822.
(3) Remove the access platform(s).

Subtask 21-26-35-862-050-A ** ON A/C NOT FOR ALL

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

[Rev.9 from 2019] 2026.04.02 06:11:03 UTC