Check for Blockage of the Demister Filter and of the Filter Cartridge with the Pressure Ports

TASK 21-26-42-200-006-A
Check for Blockage of the Demister Filter and of the Filter Cartridge with the Pressure Ports

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
No specific	AR	GAGE 0 TO 0,34 BAR (0 TO 5 PSI) - NEGATIVE PRESSURE

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
824

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-26-43-600-016-A	Discard Demister Filter Element and Filter Cartridge (LE BOZEC)
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
Check for blockage of the Demister Filter and Filter Cartridge with Pressure Ports

3. Job Set-up
Subtask 21-26-42-010-062-A ** ON A/C NOT FOR ALL

A. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at the access door 824.
(2) Open the access door 824.

Subtask 21-26-42-861-059-A ** ON A/C NOT FOR ALL

B. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

NOTE: The energization of the aircraft electrical circuits starts the full test of the ventilation system. The test continues for 2 minutes approximately.
Do not connect the manometer until this test is completed.

Subtask 21-26-42-860-056-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration

Check for blockage of the Demister Filter and Filter Cartridge with Pressure Ports ** ON A/C NOT FOR ALL

(1) Remove the protective caps (1) and (2) from the pressure ports.
(2) Connect the GAGE 0 TO 0,34 BAR (0 TO 5 PSI) - NEGATIVE PRESSURE to the pressure ports.

NOTE: The input pressure port is on the top of the filter assembly. The output pressure port is on the side of the filter assembly.

4. Procedure
Subtask 21-26-42-210-062-A ** ON A/C NOT FOR ALL

A. Check for Blockage of the Demister Filter and of the Filter Cartridge

Check for blockage of the Demister Filter and Filter Cartridge with Pressure Ports ** ON A/C NOT FOR ALL

(1) If the differential pressure is more than 29 mbar (0.42 psi):
(a) Replace the two filters (Ref. AMM TASK 21-26-43-600-016).

5. Close-up
Subtask 21-26-42-862-059-A ** ON A/C NOT FOR ALL

A. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

Subtask 21-26-42-860-057-A ** ON A/C NOT FOR ALL

B. Put the aircraft back to its initial configuration.
(1) Disconnect the manometer from the pressure ports.
(2) Install the protective caps (1) and (2) on the pressure ports.

Subtask 21-26-42-410-060-A ** ON A/C NOT FOR ALL

C. 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).

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