Reactivation of the Trim Air Valve

TASK 21-63-00-440-001-A
Reactivation of the Trim Air Valve

WARNING: MAKE SURE THAT AIR IS NOT SUPPLIED TO THE AIR CONDITIONING SYSTEM FROM THE MAIN ENGINE, THE APU OR A GROUND SOURCE. HOT COMPRESSED AIR CAN CAUSE INJURY TO PERSONNEL.

WARNING: MAKE SURE THAT THE COMPONENTS OF THE BLEED AIR SYSTEM ARE COOL. HOT COMPONENTS WILL BURN YOU.

CAUTION: BE VERY CAREFUL WHEN YOU DO WORK ON OR NEAR THE AIR-CONDITIONING DUCTS. THE DUCTS ARE MADE OF THIN MATERIAL AND YOU CAN EASILY BREAK THEM.

ZONE: 137
ZONE: 138
FIN: 11HK ** ON A/C NOT FOR ALL
FIN: 12HK ** ON A/C NOT FOR ALL
FIN: 13HK ** ON A/C NOT FOR ALL

1. Reason for the Job
MMEL 21-63-02D
COCKPIT AND CABIN TRIM AIR VALVE
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
137	BAY BETW AFT PART. BULKHEAD OF FWD CARGO
138	BAY BETW AFT PART. BULKHEAD OF FWD CARGO
191CB, 191DB, 825

C. Referenced Information

REFERENCE	DESIGNATION
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 25-54-12-000-001-A	Removal of the Forward Cargo-Compartment Partition
TASK 25-54-12-400-001-A	Installation of the Forward Cargo-Compartment Partition
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 52-30-00-860-002-A	Close the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 52-30-00-860-003-A	Open the FWD or Aft Cargo-Compartment Door with the Hand Pump
TASK 52-30-00-860-004-A	Close the FWD or Aft Cargo-Compartment Door with the Hand Pump
Trim Air Valve - Component Location ** ON A/C NOT FOR ALL
Trim Air Valve - Component Location ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 21-63-00-861-051-A ** ON A/C NOT FOR ALL

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

Subtask 21-63-00-860-059-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) In the cockpit, on AIR COND panel 30VU:
(a) Make sure that the APU BLEED pushbutton switch is released (the OFF legend is on).
(b) Make sure that the ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are released (the OFF legends are on).
(c) Make sure that the PACK 1 and the PACK 2 pushbutton switches are released (the OFF legends are on).
(d) Make sure that the HOT AIR pushbutton switch is released (the OFF legend is on).
(e) Put the WARNING NOTICE(S) in position to tell persons not to operate these pushbutton switches.
(2) At access doors 191CB and 191DB:
(a) On the LP and the HP ground connectors, put the WARNING NOTICE(S) in position to tell persons not to supply the ground air.

Subtask 21-63-00-010-056-A ** ON A/C NOT FOR ALL

C. Get Access

WARNING: DO NOT OPEN OR GO NEAR PRESSURE-SEALED DOORS WHEN THE AIRCRAFT IS PRESSURIZED. A PRESSURE-SEALED DOOR THAT OPENS WHEN THE AIRCRAFT IS PRESSURIZED:

WILL CAUSE EXPLOSIVE DECOMPRESSION.
CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAUSE DAMAGE TO THE AIRCRAFT OR EQUIPMENT.

(1) Open forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-001) or (Ref. AMM TASK 52-30-00-860-003).
(2) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at forward cargo-compartment door 825.
(3) Remove the access panels from partition FR 34 (Ref. AMM TASK 25-54-12-000-001).

Subtask 21-63-00-865-079-A ** ON A/C NOT FOR ALL

D. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS2	4HK	V20
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS1	3HK	V19
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS2	2HK	V18
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS1	1HK	V17

4. Procedure
Subtask 21-63-00-440-050-A ** ON A/C NOT FOR ALL

A. Reactivation of the Trim Air Valve

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(1) Remove the lockwire from the manual override lever (3).
(2) Remove the tie wrap(s) from the electrical connector (2) and the aircraft structure.
(3) Remove the CAP-BLANKING from each electrical connector and receptacle.

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

(4) Connect the electrical connector (2) to the trim air valve (1).

Subtask 21-63-00-865-069-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
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS2	4HK	V20
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS1	3HK	V19
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS2	2HK	V18
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS1	1HK	V17

5. Close-up
Subtask 21-63-00-410-056-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) Install the access panels at partition FR 34 (Ref. AMM TASK 25-54-12-400-001).
(3) Remove the access platform(s).
(4) Close forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-002) or (Ref. AMM TASK 52-30-00-860-004).
(5) Remove the WARNING NOTICE(S).

Subtask 21-63-00-862-059-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.02 06:11:42 UTC