Removal of the APU Bleed Check-Valve

TASK 36-12-51-000-001-A
Removal of the APU Bleed Check-Valve

WARNING: MAKE SURE THAT THE PNEUMATIC SYSTEM IS DEPRESSURIZED BEFORE YOU START WORK. PRESSURIZED AIR CAN CAUSE INJURY TO PERSONNEL.

WARNING: ALWAYS USE APPLICABLE GLOVES TO TOUCH HOT PARTS. HOT PARTS CAN CAUSE INJURY TO PERSONS.

WARNING: BE CAREFUL WHEN THE DUCTS ARE DISCONNECTED THE TEMPERATURE OF THE EXHAUST GASES FROM THE OPEN ENDS OF THE DISCONNECTED DUCTS CAN BE AS HIGH AS 270 DEG.C (518 DEG.F). THE HOT GASES CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

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.

CAUTION: DO NOT PUT YOUR WEIGHT ON THE DUCTS. IT IS VERY EASY TO BREAK THEM.

ZONE: 150
ZONE: 190
ZONE: 211
FIN: 7260HM

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
150	AFT CARGO COMPARTMENT FWD PRESS BULKHEAD TO AFT BULKHEAD OF AFT CARGO COMPARTMENT
190	BELLY FAIR, AIR CONDITIONING & HYD COMPT
211	COCKPIT
197BB
197KB

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-43-52-000-001-A	Removal of the Pressure Regulating Valve - Aft Cargo-Compartment Heating
TASK 29-00-00-910-004-A	General Rules for Removal and Installation Procedures in the Hydraulic Systems
TASK 36-12-51-200-001-A	Remove and Check the Auxiliary Power Unit (APU) Bleed Check-Valve for Condition
TASK 36-22-17-000-001-A	Removal of the APU Overheat Sensing-Elements
TASK 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from the Belly Fairing Structure
APU Bleed Check-Valve ** ON A/C NOT FOR ALL
APU Bleed Check-Valve ** ON A/C NOT FOR ALL
APU Bleed Check-Valve ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 36-12-51-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 1/CTL	3HA1	D12
49VU	AIR BLEED/ENG 1/MONG	2HA1	D11
** ON A/C ALL
49VU	AIR BLEED/X FEED/VALVE/BAT	2HV	D13
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 2/MONG	3HA2	D12
49VU	AIR BLEED/ENG 1/CTL	2HA1	D11
** ON A/C NOT FOR ALL
122VU	AIR BLEED/ENG 2/CTL	3HA2	Z23
122VU	AIR BLEED/ENG 2/MONG	2HA2	Z22
** ON A/C ALL
122VU	AIR BLEED/X FEED VALVE/NORM	1HV	Z20
** ON A/C NOT FOR ALL
122VU	AIR BLEED/ENG 1/MONG	3HA1	Z23
122VU	AIR BLEED/ENG 2/CTL	2HA2	Z22

Subtask 36-12-51-860-050-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Put the WARNING NOTICE(S) in position:

in the cockpit on the Engine Control Panel 115VU to tell persons not to start the engine(s),
in the cockpit on the AIR COND Overhead Control Panel 30VU to tell persons not to push in the APU BLEED pushbutton switch,
on the HP ground connector to tell persons not to pressurize the pneumatic system.

(2) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below the access panel 197BB.

Subtask 36-12-51-010-050-A ** ON A/C NOT FOR ALL

C. Remove access panel 197BB (Ref. AMM TASK 53-35-13-000-002).

Subtask 36-12-51-860-050-C ** ON A/C NOT FOR ALL

D. Aircraft Maintenance Configuration
(1) Put the WARNING NOTICE(S) in position:

in the cockpit on the Engine Control Panel 115VU to tell persons not to start the engine(s),
in the cockpit on the AIR COND Overhead Control Panel 30VU to tell persons not to push in the APU BLEED pushbutton switch,
on the HP ground connector to tell persons not to pressurize the pneumatic system.

(2) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below the access panel 197KB.

Subtask 36-12-51-010-050-C ** ON A/C NOT FOR ALL

E. Remove access panel 197KB (Ref. AMM TASK 53-35-13-000-002).

4. Procedure
Subtask 36-12-51-020-055-A ** ON A/C NOT FOR ALL

A. Removal of the APU Bleed Check-Valve
(1) If necessary, remove the hydraulic pipe line (Ref. AMM TASK 29-00-00-910-004).

CAUTION: REMOVE OR INSTALL THE SENSING ELEMENTS CAREFULLY. DO NOT TWIST, BEND OR CAUSE KINKS IN THE SENSING ELEMENTS. IF YOU DO, YOU CAN CAUSE DAMAGE TO THEM.

(2) Remove the APU overheat sensing-elements (15) from the elbow bleed air duct (2) (Ref. AMM TASK 36-22-17-000-001).
(3) Remove the bolts (18) and the washers (17) from the bracket (16).
(4) Loosen the screw of the clamp (19).
(5) Remove the clamp (19) from the bleed air duct (9).
(6) Remove the nut (4), washer (5), bonding strap (8) and bolt (10) from the bleed air duct (2).
(7) Safety the bonding strap (8) on the bleed air duct (9).
(8) Remove the nuts (7), the washers (6) and the bolts (1) from the bleed air ducts (2) and (9).
(9) Remove the connecting rods (3) from the bleed air ducts (2) and (9).

CAUTION: SOME PRESSURE CAN STAY IN THE DUCTING. THE PRESSURE WILL DECREASE WHEN YOU RELEASE THE CLAMPS.

(10) Loosen the bolt of the clamp (14) installed on the bleed air duct (2) and the housing (11).
(11) Carefully pull the bleed air duct (2) away from the housing (11) to get access to the APU bleed check-valve (13).
(12) Remove the clamp (14) from the bleed air duct (2).
(13) Remove the APU bleed check-valve (13) from the housing (11):
(a) Make sure that the parts of the APU bleed check-valve (the flap, the shaft and the spring) are not missing (Ref. AMM TASK 36-12-51-200-001).
(b) If the part(s) is (are) missing, do the step that follow before you install the new APU bleed check-valve:
1 Do an inspection of the APU bleed-air system and the air conditioning system to find the missing parts.
(14) Remove and discard the O-ring (12).
(15) Put the PLUG-BLANKING in each disconnected line end.

Subtask 36-12-51-020-055-B ** ON A/C NOT FOR ALL

A. Removal of the APU Bleed Check-Valve
(1) If necessary, remove the hydraulic pipe line (Ref. AMM TASK 29-00-00-910-004).

CAUTION: REMOVE OR INSTALL THE SENSING ELEMENTS CAREFULLY. DO NOT TWIST, BEND OR CAUSE KINKS IN THE SENSING ELEMENTS. IF YOU DO, YOU CAN CAUSE DAMAGE TO THEM.

(2) Remove the APU overheat sensing-elements (15) from the bleed air duct (2) (Ref. AMM TASK 36-22-17-000-001).
(3) Remove the bolts (21) and the washers (20) from the bracket (19).

CAUTION: SOME PRESSURE CAN STAY IN THE DUCTING. THE PRESSURE WILL DECREASE WHEN YOU RELEASE THE CLAMPS.

(4) Loosen the bolt of the clamp (17).
(5) Disconnect the bleed air duct (2) from the Pressure Regulating Valve (PRV) (16).
(6) If necessary, remove the PRV (16) (Ref. AMM TASK 21-43-52-000-001).
(7) Remove the clamp (17).
(8) Remove and discard the O-ring (18).
(9) Loosen the screw of the clamp (22).
(10) Remove the clamp (22) from the bleed air duct (9).
(11) Remove the nut (4), washer (5), bonding strap (8) and bolt (10) from the bleed air duct (2).
(12) Safety the bonding strap (8) on the bleed air duct (9).
(13) Remove the nuts (7), the washers (6) and the bolts (1) from the bleed air ducts (2) and (9).
(14) Remove the connecting rods (3) from the bleed air ducts (2) and (9).

CAUTION: SOME PRESSURE CAN STAY IN THE DUCTING. THE PRESSURE WILL DECREASE WHEN YOU RELEASE THE CLAMPS.

(15) Loosen the bolt of the clamp (14) installed on the bleed air duct (2) and the housing (11).
(16) Carefully pull the bleed air duct (2) away from the housing (11) to get access to the APU bleed check-valve (13).
(17) Remove the clamp (14) from the bleed air duct (2).
(18) Remove the APU bleed check-valve (13) from the housing (11):
(a) Make sure that the parts of the APU bleed check-valve (the flap, the shaft and the spring) are not missing (Ref. AMM TASK 36-12-51-200-001).
(b) If the part(s) is (are) missing, do the step that follow before you install the new APU bleed check-valve:
1 Do an inspection of the APU bleed-air system and the air conditioning system to find the missing parts.
(19) Remove and discard the O-ring (12).
(20) Put the PLUG-BLANKING in each disconnected line end.

[Rev.10 from 2021] 2026.04.01 12:38:05 UTC