Deactivation of the Window Heat Computer (WHC)

TASK 30-42-00-040-001-A
Deactivation of the Window Heat Computer (WHC)

FIN: 2DG1
FIN: 2DG2

1. Reason for the Job
MMEL 30-42-01A
WINDOW HEAT COMPUTER
To do the deactivation of one of the two WHCs and to do a check of the correct operation and monitoring of the WHC that stays in operation.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 30-42-00-710-001-A	Operational Test of the Windshield Anti-Icing and Defogging
TASK 31-60-00-860-001-A	EIS Start Procedure
TASK 31-60-00-860-002-A	EIS Stop Procedure

3. Job Set-up
Subtask 30-42-00-861-052-A

A. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 30-42-00-869-059-A

B. Do the EIS start procedure (upper ECAM DU and lower ECAM DU only)
(Ref. AMM TASK 31-60-00-860-001).

4. Procedure
Subtask 30-42-00-710-056-A

A. Check of the Heaters of the Fixed and Sliding Windows related to the WHC in Operation
(1) Do an operational test of the available windshield anti-icing and defogging system (Ref. AMM TASK 30-42-00-710-001).

Subtask 30-42-00-865-056-A

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
FOR FIN: 2DG1 (WHC1)
122VU	ANTI ICE/WINDOWS/L	4DG1	X14
122VU	ANTI ICE/WHC/1	5DG1	X13
123VU	ANTI ICE/L/WHSLD	1DG1	AF10
FOR FIN: 2DG2 (WHC2)
122VU	ANTI ICE/WINDOWS/R	4DG2	W14
122VU	ANTI ICE/WHC/2	5DG2	W13
123VU	ANTI ICE/R/WHSLD	1DG2	AF03

Subtask 30-42-00-210-050-A

C. Check of the Warning Messages of the Fixed and Sliding Windows related to the WHC in Operation
(1) On the Upper ECAM DU make sure that these warning messages:

A.ICE L WSHLD HEAT
A.ICE R WSHLD HEAT
A.ICE L WINDOW HEAT
A.ICE R WINDOW HEAT

come into view.

Subtask 30-42-00-860-058-A

D. Circuit Breaker Configuration
(1) The circuit breakers of the WHC that does not operate, must stay open, safetied and tagged.
(2) Remove the safety clip(s) and tag(s) and close this(these) circuit breaker(s) that follow of the WHC that stays in operation:

Subtask 30-42-00-865-057-A

E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
FOR FIN: 2DG1 (WHC1)
122VU	ANTI ICE/WINDOWS/L	4DG1	X14
122VU	ANTI ICE/WHC/1	5DG1	X13
123VU	ANTI ICE/L/WHSLD	1DG1	AF10
FOR FIN: 2DG2 (WHC2)
122VU	ANTI ICE/WINDOWS/R	4DG2	W14
122VU	ANTI ICE/WHC/2	5DG2	W13
123VU	ANTI ICE/R/WHSLD	1DG2	AF03

5. Close-up
Subtask 30-42-00-869-060-A

A. Make an entry in the log book.

Subtask 30-42-00-869-061-A

B. Do the EIS stop procedure
(Ref. AMM TASK 31-60-00-860-002).

Subtask 30-42-00-862-052-A

C. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 00:30:53 UTC