Removal of the Sense Line between the Bleed-Air Precooler Exchanger (Upstream) and the Bleed Differential Pressure-Transducer

TASK 36-11-49-000-826-A
Removal of the Sense Line between the Bleed-Air Precooler Exchanger (Upstream) and the Bleed Differential Pressure-Transducer

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

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

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

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE 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.

ZONE: 413
ZONE: 423

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 4M (13 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
413	UPPER FWD PYLON
423	UPPER FWD PYLON
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AT, 413BT, 413CT, 413DT
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AT, 423BT, 423CT, 423DT

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 49-00-00-860-009-A	APU Shutdown by External Power (131-9(A))
TASK 49-00-00-860-009-A-01	APU Shutdown by Batteries (131-9(A))
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
Sense Line between the Bleed-Air Precooler Exchanger (Upstream) and the Bleed Differential Pressure-Transducer

3. Job Set-up
Subtask 36-11-49-861-114-A ** ON A/C NOT FOR ALL

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

Subtask 36-11-49-941-133-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) Make sure that the engine 1(2) shutdown occurred not less than five minutes before you do this procedure.
(2) On AIR COND panel 30VU:
(a) Make sure that the ENG 1(2) BLEED pushbutton switch is released (OFF legend on).
(b) Make sure that the APU BLEED pushbutton switch is released (ON legend off).
(c) Put a WARNING NOTICE(S) in position to tell persons not to operate the pneumatic system.
(3) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).
(4) On the HP ground connector:
(a) Put a WARNING NOTICE(S) in position to tell persons not to pressurize the pneumatic system.

Subtask 36-11-49-865-198-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
49VU	AIR BLEED/ENG 1/CTL	2HA1	D11
122VU	AIR BLEED/ENG 1/MONG	3HA1	Z23
FOR FIN: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
49VU	AIR BLEED/ENG 2/MONG	3HA2	D12
122VU	AIR BLEED/ENG 2/CTL	2HA2	Z22

Subtask 36-11-49-010-233-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position at the pylon access panels.
(2) Remove these access panels:
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AT 413BT 413CT 413DT
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AT 423BT 423CT 423DT

4. Procedure
Subtask 36-11-49-020-146-A ** ON A/C NOT FOR ALL

A. Removal of the Sense Line between the Bleed-Air Precooler Exchanger (Upstream) and the Bleed Differential Pressure-Transducer
(1) If you use the APU to energize the electrical circuits, stop the APU:

For GTCP 36-300 APU (Ref. AMM D/O 49-00-00-86)
For APS 3200 APU (Ref. AMM D/O 49-00-00-86)
For 131-9(A) APU (Ref. AMM TASK 49-00-00-860-009).

(2) In the cockpit, on the SD bleed page:
(a) Make sure that the pressure and the temperature of the bleed-air duct system are in ambient conditions.

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

WARNING: DO NOT TOUCH THE UNIT UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

(3) Remove the two grommets (2) of the sense line (1).
(4) Disconnect the nut (4) of the sense line (1) from the port of the bleed differential pressure-transducer (3).
(5) Disconnect the nut (5) of the sense line (1) from the port of the bleed-air precooler (6).
(6) Remove the sense line (1).
(7) Put PLUG - BLANKING on the ports of the bleed-air precooler (6) and the bleed differential pressure-transducer (3).
(8) Put the PLUG-BLANKING in each disconnected line end.

[Rev.10 from 2021] 2026.04.01 12:38:01 UTC