Removal of the Pressure Sub-System [CFML]

TASK 73-21-45-000-801-A
Removal of the Pressure Sub-System

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

ZONE: 210
ZONE: 400
FIN: 4700KS

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 1M(3 FT)
No specific	AR	CAP - PROTECTION
No specific	AR	COVER - PROTECTION
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 73-21-55-860-801-A	Full Download of all Electronic Engine Control (EEC) Data (On-Wing)
Pressure Sub-System

3. Job Set-up
Subtask 73-21-45-941-051-A

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put WARNING NOTICE(S) in position to tell persons not to operate:

the ENG/MODE selector switch
the ENG/MASTER 1(2) control switch

(2) On the ENG section of maintenance panel 50VU:
(a) Make sure that the ON legend of FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) is in position to tell persons not to energize FADEC 1(2).

Subtask 73-21-45-010-051-A

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.

4. Procedure
Subtask 73-21-45-020-050-A

A. Removal of the Pressure Sub-System (1)

NOTE: Complex electrical components have a high no fault found rate during component investigations at the vendor. Electronic Engine Control (EEC) Non-Volatile Memory (NVM) and continuous engine operational data can be helpful to identify the root cause of these faults. If you remove the pressure sub-system (1) for vendor investigation in which maintenance actions done again and again or component replacements have failed to identify the root cause, consider EEC NVM and continuous engine operational data download (Ref. AMM TASK 73-21-55-860-801).

(1) Disconnect the data entry plug (2) from the pressure sub-system receptacle (3).
(2) Disconnection of the harness electrical connectors from the applicable receptacles of the pressure sub-system (1):

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.

(a) Disconnect the HJ6A harness electrical connector (4) from the pressure sub-system (1).
(b) Disconnect the HJ6B harness electrical connector (5) from the pressure sub-system (1).
(3) Disengagement of the air tubes from the pressure sub-system (1):

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.

(a) Cut and remove the two safety wires from the coupling nuts (6) and (7).
(b) Loosen the PS3 air tube coupling nut (6).
(c) Loosen the P3B air tube coupling nut (7).
(d) Loosen the PS12 air tube coupling nut (8).
(4) Removal of the pressure sub-system (1):
(a) Remove the three bolts (9) from the three mounting brackets (10).
(b) Remove the pressure sub-system (1) from the three mounting brackets (10).
(5) Install COVER - PROTECTION and CAP - PROTECTION on all the open ports, open tubes, open hoses and connectors.

[Rev.10 from 2021] 2026.04.01 03:04:52 UTC