EGT Harness Dry-Out Procedure [IAE]

TASK 77-21-43-350-801-A
EGT Harness Dry-Out Procedure

1. Reason for the Job
This task can be used to remove moisture from the Exhaust Gas Temperature (EGT) harness with and without junction box.
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	1	AIR SOURCE 5 BAR (72.5 PSI)
No specific	1	NITROGEN COMPRESSED SOURCE 5 BAR (72.5 PSI) - (DRY)
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-13-00-410-010-A	Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 78-30-00-040-012-A	Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance
TASK 78-30-00-440-012-A	Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after Ground Maintenance
TASK 78-32-00-010-010-A	Opening of the Thrust Reverser Halves
TASK 78-32-00-410-010-A	Closing of the Thrust Reverser Halves
Direction of Nitrogen or Hot Air for Dry-Out of EGT Junction Box

3. Job Set-up
Subtask 77-21-43-941-058-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Put a WARNING NOTICE(S) in position to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than five minutes before you do this procedure.
(3) 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 the FADEC 1(2).

Subtask 77-21-43-010-068-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
(2) Put the ACCESS PLATFORM 1M(3 FT) in position.

Subtask 77-21-43-040-060-A ** ON A/C NOT FOR ALL

C. Deactivate the Thrust Reverser

WARNING: MAKE SURE THAT THE THRUST REVERSER HYDRAULIC CONTROL UNIT (HCU) IS DEACTIVATED BEFORE YOU DO WORK ON OR AROUND THE THRUST REVERSER. IF THE HCU IS NOT DEACTIVATED, THERE IS A RISK OF UNWANTED THRUST REVERSER OPERATION WHICH CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Deactivate the thrust reverser Hydraulic Control Unit (HCU) (Ref. AMM TASK 78-30-00-040-012).

Subtask 77-21-43-010-069-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser halves (Ref. AMM TASK 78-32-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.

4. Procedure
Subtask 77-21-43-350-051-A ** ON A/C NOT FOR ALL

A. Dry the components with compressed nitrogen
PRE SBE 77-0015
Apply NITROGEN COMPRESSED SOURCE 5 BAR (72.5 PSI) - (DRY) or AIR SOURCE 5 BAR (72.5 PSI) for approximately three minutes to remove moisture from the EGT harness and junction box.

Direction of Nitrogen or Hot Air for Dry-Out of EGT Junction Box ** ON A/C NOT FOR ALL

END OF PRE SBE 77-0015
POST SBE 77-0015
Apply NITROGEN COMPRESSED SOURCE 5 BAR (72.5 PSI) - (DRY) or AIR SOURCE 5 BAR (72.5 PSI) for approximately three minutes to remove moisture from the EGT harness.
END OF POST SBE 77-0015

5. Close-up
Subtask 77-21-43-410-063-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the access platform(s).
(3) Close the thrust reverser halves (Ref. AMM TASK 78-32-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR.

Subtask 77-21-43-440-056-A ** ON A/C NOT FOR ALL

B. Activate the thrust reverser HCU (Ref. AMM TASK 78-30-00-440-012).

Subtask 77-21-43-410-064-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls (Ref. AMM TASK 71-13-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
(2) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 13:00:47 UTC