Deactivation of the Aft-Cargo-Compartment Ventilation Isolation-Valves

TASK 21-28-00-040-002-A
Deactivation of the Aft-Cargo-Compartment Ventilation Isolation-Valves

ZONE: 150
ZONE: 160
ZONE: 170
FIN: 33HN ** ON A/C NOT FOR ALL
FIN: 34HN ** ON A/C NOT FOR ALL
Task Summary

Access	Test	Specific Tools	Mhr	E/T	Nb Men
YES	YES	NO	0.5	0.5	1

1. Reason for the Job
MMEL 21-28-04B
AFT CARGO ISOLATION VALVE
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT)
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
150	AFT CARGO COMPARTMENT FWD PRESS BULKHEAD TO AFT BULKHEAD OF AFT CARGO COMPARTMENT
160	BULK CARGO COMPARTMENT AFT BULKHEAD OF AFT CARGO COMPARTMENT TO AFT BULKHEAD OF BULK CARGO COMPARTMENT
170	AFT CAB U/FLOOR COMPT AFT BHD OF BULK
826
FOR [33HN] (ISOL VALVE AFT CARGO OUTLET)
162DW
FOR [34HN] (ISOL VALVE AFT CARGO INLET)
151EW
151VW

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 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
Cargo-Compartment Ventilation Isolation-Valves ** ON A/C NOT FOR ALL
Cargo-Compartment Ventilation Isolation-Valves ** ON A/C NOT FOR ALL
FOR [33HN] (ISOL VALVE AFT CARGO OUTLET)
TASK 25-55-12-000-001-A	Removal of the Aft Cargo-Compartment Partition at FR65
TASK 25-55-12-400-001-A	Installation of the Aft Cargo-Compartment Partition at FR65
FOR [34HN] (ISOL VALVE AFT CARGO INLET)
TASK 25-55-11-000-003-A	Removal of the Sidewall Panels in the Aft Cargo Compartment - FR47/FR59
TASK 25-55-11-400-003-A	Installation of the Sidewall Panels in the Aft Cargo Compartment - FR47/FR59

3. Job Set-up
Subtask 21-28-00-861-058-A ** ON A/C NOT FOR ALL

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

Subtask 21-28-00-865-085-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR COND/AFT CARGO/VENT/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
49VU	AIR COND/AFT CARGO/VENT & HTG/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
122VU	AIR COND/AFT CARGO VENT/FAN	30HN	S22

Subtask 21-28-00-010-055-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) below the aft cargo-compartment door (door 826).
(2) Open the aft cargo-compartment door (Ref. AMM TASK 52-30-00-860-001).
(3) FOR [33HN] (ISOL VALVE AFT CARGO OUTLET)
Remove access panel 162DW (Ref. AMM TASK 25-55-12-000-001).
(4) FOR [34HN] (ISOL VALVE AFT CARGO INLET)
Remove access panel 151EW (Ref. AMM TASK 25-55-11-000-003).

Subtask 21-28-00-010-055-C ** ON A/C NOT FOR ALL

4. Procedure
Subtask 21-28-00-040-053-A ** ON A/C NOT FOR ALL

A. Deactivation of the Aft-Cargo-Compartment Ventilation Isolation-Valves

Cargo-Compartment Ventilation Isolation-Valves ** ON A/C NOT FOR ALL

(1) On the isolation valves (2), move the manual override levers (1) to the closed position.
(2) Disconnect the electrical connectors (3) (33HN-A and 34 HN-A) and safety them to the aircraft structure.
(3) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

5. Close-up
Subtask 21-28-00-865-092-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
122VU	AIR COND/AFT CARGO VENT/FAN	30HN	S22

Subtask 21-28-00-865-093-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/AFT CARGO/VENT/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
49VU	AIR COND/AFT CARGO/VENT & HTG/CTL & MONG	31HN	C07

Subtask 21-28-00-410-056-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) FOR [33HN] (ISOL VALVE AFT CARGO OUTLET)
Install access panel 162DW (Ref. AMM TASK 25-55-12-400-001).
(3) FOR [34HN] (ISOL VALVE AFT CARGO INLET)
Install access panel 151EW (Ref. AMM TASK 25-55-11-400-003).
(4) Make an entry in the aircraft log book to record the deactivation.
(5) Close the aft cargo-compartment door (Ref. AMM TASK 52-30-00-860-002).
(6) Remove the access platform(s).

Subtask 21-28-00-410-056-C ** 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) FOR [33HN] (ISOL VALVE AFT CARGO OUTLET)
Install access panel 162DW (Ref. AMM TASK 25-55-12-400-001).
(3) FOR [34HN] (ISOL VALVE AFT CARGO INLET)
Install access panel 151VW (Ref. AMM TASK 25-55-11-400-003).
(4) Make an entry in the aircraft log book to record the deactivation.
(5) Close the aft cargo-compartment door (Ref. AMM TASK 52-30-00-860-002).
(6) Remove the access platform(s).

Subtask 21-28-00-862-056-A ** ON A/C NOT FOR ALL

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

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