Functional Test of the Magnetic Bars [CFML]

TASK 79-21-05-720-801-A
Functional Test of the Magnetic Bars

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.

WARNING: DO NOT TOUCH THE FUEL OR OIL SYSTEM COMPONENTS FOR A SHORT TIME AFTER THE ENGINE IS SHUT DOWN. THE ENGINE COMPONENTS STAY HOT FOR SOME TIME AND CAN CAUSE INJURY.

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

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	CARBON STEEL BALL
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 71-13-00-410-803-A	Closing of the Fan Cowl Doors
TASK 79-21-05-000-801-A	Removal of the Scavenge Screen Plugs
TASK 79-21-05-400-801-A	Installation of the Scavenge Screen Plugs
Magnetic Bar for Radial Test
Magnetic Bar for Axial Test

3. Job Set-up
Subtask 79-21-05-941-062-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 79-21-05-010-059-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

4. Procedure
Subtask 79-21-05-720-050-A

A. Functional Test of the Magnetic Bars
(1) Remove the both scavenge screen plugs (Ref. AMM TASK 79-21-05-000-801).
(2) Test each magnetic bar as follows:
(a) Check of the radial magnetic pull force:

Magnetic Bar for Radial Test

1 Hold the scavenge screen plugs horizontally and stick a 0.393 in. (10.0 mm) CARBON STEEL BALL in M50 material (or an equivalent material) next to the magnetic bar. The ball must not drop.
a If the ball does not stick the magnetic bar, replace the defective scavenge screen plug (Ref. AMM TASK 79-21-05-400-801).
(b) Check of the axial magnetic pull force:

Magnetic Bar for Axial Test

1 Hold the scavenge screen plug vertically and stick a 0.393 in. (10.0 mm) CARBON STEEL BALL in M50 material (or an equivalent material) next to the magnetic bar. The ball must not drop.
a If the ball does not stick the magnetic bar, replace the scavenge screen plug (Ref. AMM TASK 79-21-05-400-801).

5. Close-up
Subtask 79-21-05-410-055-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 WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:43:08 UTC