Removal of the Main Heat Exchanger [CFML]

TASK 79-21-25-000-801-A
Removal of the Main Heat Exchanger

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.

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)-ADJUSTABLE
No specific	AR	CAP - PROTECTION
No specific	1	CONTAINER 5 L (1.32 USGAL)
No specific	AR	COVER - PROTECTION
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
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 79-21-25-680-801-A	Draining of the Main Heat Exchanger
Main Heat Exchanger

3. Job Set-up
Subtask 79-21-25-941-050-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, and
The ENG/MASTER 1(2) control switch.

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

Subtask 79-21-25-010-050-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 the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE in position.

4. Procedure
Subtask 79-21-25-020-050-A

A. Removal of the Main Heat Exchanger
(1) Put a CONTAINER 5 L (1.32 USGAL) below the main heat exchanger (1).
(2) Drain the main heat exchanger (1) (Ref. AMM TASK 79-21-25-680-801).
(3) Disconnection of the fuel tubes from the main heat exchanger (1):

WARNING: WHEN YOU USE ENGINE FUEL, USE PERSONAL PROTECTION EQUIPMENT AND DO IT IN A WELL-VENTILATED AREA. ENGINE FUEL IS TOXIC.

(a) Remove the four bolts (3) from the fuel tube (2).
(b) Disconnect the fuel tube (2) from the main heat exchanger (1).
(c) Remove and discard the gasket (4) from the fuel tube (2).
(d) Remove the four bolts (6) from the fuel tube (5).
(e) Disconnect the fuel tube (5) from the main heat exchanger (1).
(f) Remove and discard the gasket (7) from the fuel tube (5).
(4) Disconnection of the oil tubes from the main heat exchanger (1):

WARNING: USE PERSONAL PROTECTION EQUIPMENT. USE THE ENGINE OIL IN A WELL-VENTILATED AREA. ENGINE OIL IS TOXIC.

(a) Remove the four bolts (9) from the oil tube (8).
(b) Disconnect the oil tube (8) from the main heat exchanger (1).
(c) Remove and discard the gasket (10) from the oil tube (8).
(d) Remove the four bolts (12) from the oil tube (11).
(e) Disconnect the oil tube (11) from the main heat exchanger (1).
(f) Remove and discard the gasket (13) from the oil tube (11).
(g) Loosen the thread of the coupling nut (15) of the oil tube (14).
(h) Disconnect the oil tube (14) from the main heat exchanger (1).
(5) Remove the four bolts (16) equipped with the captive washers that attach the main heat exchanger (1) to the three mounting brackets (18).
(6) Remove the main heat exchanger (1) from the three mounting brackets (18).
(7) Install the COVER - PROTECTION and CAP - PROTECTION on all the open ports, tubes, hoses and connectors.
(8) Remove the CONTAINER 5 L (1.32 USGAL) from below the main heat exchanger (1).

[Rev.10 from 2021] 2026.04.01 03:43:11 UTC