Draining of the Main Heat Exchanger [CFML]
TASK 79-21-25-680-801-A
Draining of the Main Heat Exchanger
Protect the engine for the Draining of the Main Fuel Heat Exchanger.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 79-21-25-941-052-A
Subtask 79-21-25-410-051-A
[Rev.10 from 2021]
2026.04.01 03:43:10 UTC
Draining 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.
ZONE: 400
1. Reason for the JobProtect the engine for the Draining of the Main Fuel Heat Exchanger.
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 | WARNING NOTICE(S) |
| No specific | Torque wrench: range to between 97.65 and 88.35 lbf.in (1.10 and 1.00 m.daN ) ![]() |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1) | |
| 437AL, 438AR | |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2) | |
| 447AL, 448AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-13-79-610-807-A | Flushing of the Oil System |
| TASK 71-13-00-010-803-A | Opening of the Fan Cowl Doors |
| TASK 71-13-00-410-803-A | Closing of the Fan Cowl Doors |
Subtask 79-21-25-941-052-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 a WARNING NOTICE(S) in position to tell persons not to operate:
(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 79-21-25-010-052-A (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 a WARNING NOTICE(S) in position to tell persons not to operate:
- The ENG/MODE selector switch
- The ENG/MASTER 1(2) control switch.
(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).
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)-ADJUSTABLE in position.
4. Procedure(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)-ADJUSTABLE in position.
WARNING:
USE PERSONAL PROTECTION EQUIPMENT. USE THE ENGINE OIL IN A WELL-VENTILATED AREA. ENGINE OIL IS TOXIC.
Subtask 79-21-25-680-050-A A. Drain the main heat exchanger (1) as follows:
(1) Remove the cap assembly (2).
(2) Allow the main heat exchanger (1) to drain.
(3) Install the cap assembly (2).
(4) TORQUE the cap assembly to between 97.65 and 88.35 lbf.in (1.10 and 1.00 m.daN )
.
Subtask 79-21-25-680-051-A (1) Remove the cap assembly (2).
(2) Allow the main heat exchanger (1) to drain.
(3) Install the cap assembly (2).
(4) TORQUE the cap assembly to between 97.65 and 88.35 lbf.in (1.10 and 1.00 m.daN )
. B. Alternative Procedure - Oil System Contamination
(1) Drain the oil system (Ref. AMM TASK 12-13-79-610-807).
5. Close-up(1) Drain the oil system (Ref. AMM TASK 12-13-79-610-807).
Subtask 79-21-25-410-051-A
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).
Main Heat Exchanger