Installation of the Avionics Equipment Blowing and Extraction Ducts

TASK 21-26-42-400-002-A
Installation of the Avionics Equipment Blowing and Extraction Ducts

1. Reason for the Job
To do the maintenance of the strake on the right side of the fuselage.
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
128EG, 824

C. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
2	O-RING	AIPC 21-26-01-08-030
21	ORING	AIPC 21-26-01-08-030
10	ORING	AIPC 21-26-01-14-410
2	O-RING	AIPC 21-26-81-08-050
21	ORING	AIPC 21-26-81-08-050

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 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
TASK 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
TASK 53-12-13-000-001-A	Removal of the avionics compartment floor panels
TASK 53-12-13-400-001-A	Installation of the avionics compartment floor panels
Avionics Equipment Extraction-Ducts
Avionics Equipment Blowing-Duct

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 21-26-42-860-055-A

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

Subtask 21-26-42-865-060-A

B. 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

Subtask 21-26-42-010-061-A

C. 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 (Ref. AMM TASK 52-41-00-010-002).
(3) Make sure that the access panel 128EG is removed (Ref. AMM TASK 53-12-13-000-001).

4. Procedure
Subtask 21-26-42-420-056-A

A. Installation of the Avionics Equipment Extraction-Ducts

Avionics Equipment Extraction-Ducts

(1) Make sure that the parts retained from the removed component are clean and in the correct condition.
(2) Remove the PLUG-BLANKING from each disconnected line end.
(3) Install a new AIPC 21-26-01-14-410 ORING (10) in the groove of the duct (9).
(4) Put the duct (9) in position.
(5) Install the clamp (11) and tighten it.
(6) Install the flexible sleeve (13).
(7) Make sure that the flexible sleeve (13) is in position between the two red markings.
(8) Install the clamps (12).
(9) Install a new AIPC 21-26-01-08-030 O-RING (2) or AIPC 21-26-81-08-050 O-RING (2) in the groove of the extract fan (1).
(10) Put the duct (4) in position.
(11) Install the sleeve (5) and the clamp (6).
(12) Tighten the clamp (6).
(13) Put the flexible sleeve (8) in position on duct (9) and (4).
(14) Make sure that the flexible sleeve (8) is in position between the two red markings.
(15) Install the clamps (7).
(16) Make sure that the distance between the two red markings of the ducts is 90 -5 mm or +5 mm (3.543 -0.197 in. or +0.197 in.).
(17) Tighten the clamps (12) and (7).
(18) Install the clamp (3) and tighten it.

Subtask 21-26-42-420-057-A

B. Installation of the Avionics Equipment Blowing-Duct

Avionics Equipment Blowing-Duct

(1) Make sure that the parts retained from the removed component are clean and in the correct condition.
(2) Remove the PLUG-BLANKING from each disconnected line end.
(3) Install a new AIPC 21-26-01-08-030 ORING (21) or AIPC 21-26-81-08-050 ORING (21) in the groove of the blower fan (20).
(4) Put the duct (14) in position.
(5) Install the clamp (15). Do not fully tighten at this time.
(6) Put the flexible sleeve (19) in position.
(7) Make sure that the flexible sleeve (19) is in position between the two red markings.
(8) Install the clamps (18).
(9) Make sure that the distance between the two red markings of the ducts is 90 -5 mm or +5 mm (3.543 -0.197 in. or +0.197 in.).
(10) Tighten the clamps (18).
(11) Put the clamp (17) in position and connect the drain hose (16) to the duct (14).
(12) Tighten the clamp (17).
(13) Make sure that the O-ring (21) is correctly installed in the groove of the blower fan (20).
(14) Install the clamp (22) and tighten it.
(15) Tighten the clamp (15).

5. Close-up
Subtask 21-26-42-410-059-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel 128EG (Ref. AMM TASK 53-12-13-400-001).
(3) Close the access door 824 (Ref. AMM TASK 52-41-00-410-002).
(4) Remove the access platform(s).

Subtask 21-26-42-865-061-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 21-26-42-862-058-A

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

[Rev.10 from 2021] 2026.04.02 06:11:05 UTC