Avionics Ventilation System Bite Survey

TASK 21-26-00-810-836-A
Avionics Ventilation System Bite Survey

1. Possible Causes

AEVC [10HQ]
SDAC-1 [1WV1]
SDAC-2 [1WV2]
wiring
VALVE-SKIN AIR INLET, AVNCS VENT [15HQ]
VALVE-SKIN AIR OUTLET, AVNCS VENT [22HQ]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 21-26-00-710-001	Operational Check of the Avionics Equipment Ventilation-System via MCDU
AMM 21-26-00-710-008	Operational Test to Read the CFDS for CLASS 3 Faults of the AEVC
AMM 21-26-00-710-009	Operational Test to Read the CFDS for LAST LEG REPORT of the AEVC
ASM 212602
ASM 212603
AMM 21-26-34-000-001	Removal of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-34-400-001	Installation of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-52-000-001	Removal of the Avionics-Ventilation Skin Air-Inlet-Valve
AMM 21-26-52-400-001	Installation of the Avionics-Ventilation Skin Air-Inlet-Valve
AMM 21-26-53-000-002	Removal of the Skin Air Outlet-Valve
AMM 21-26-53-400-001	Installation of the Skin Air Outlet-Valve
AMM 31-55-34-000-001	Removal of the SDAC
AMM 31-55-34-400-001	Installation of the SDAC

3. Fault Confirmation
Subtask 21-26-00-865-067-A

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	AIR COND/AVNCS/VENT/MONG	3HQ	Y17

Subtask 21-26-00-710-114-A

B. Test
(1) Do the reset of the AEVC (10HQ).
(a) Open the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(b) Wait for five seconds.
(c) Close the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(2) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
(3) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
(4) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.

4. Fault Isolation
Subtask 21-26-00-810-093-A

A. If the fault symptom is identified by the ECAM warning VENT AVNCS SYS FAULT with no maintenance message AEVC and/or if the LAST LEG REPORT (LLR) shows no related CFDS message:

NOTE: On the ground, the ECAM warning VENT SKIN VALVE FAULT cannot come into view during the maintenance operations. It is replaced by the ECAM warning VENT AVNCS SYS FAULT.

Replace the AEVC [10HQ] AMM 21-26-34-000-001 and AMM 21-26-34-400-001.

(1) If the fault continues:

Replace the SDAC-1 [1WV1] and the SDAC-2 [1WV2] AMM 31-55-34-000-001 and AMM 31-55-34-400-001.

(2) If the fault continues:

Do a check and repair the wiring ASM 212602 ASM 212603 between:
. Pin AB/8A of the AEVC (10HQ) and pin AD/12C of the SDAC-1 (1WV1)
. Pin AB/8A of the AEVC (10HQ) and pin AD/12C of the SDAC-2 (1WV2)
. Pin A/M of the skin air-inlet valve (15HQ) and pin AD/11C of the SDAC-1 (1WV1)
. Pin A/M of the skin air-inlet valve (15HQ) and pin AD/11C of the SDAC-2 (1WV2)
. Pin A/J of the skin air-inlet valve (15HQ) and pin AD/10F of the SDAC-1 (1WV1)
. Pin A/J of the skin air-inlet valve (15HQ) and pin AD/10F of the SDAC-2 (1WV2)
. Pin A/J of the skin air-outlet valve (22HQ) and pin AD/9D of the SDAC-1 (1WV1)
. Pin A/J of the skin air-outlet valve (22HQ) and pin AD/9D of the SDAC-2 (1WV2)
. Pin A/M of the skin air-outlet valve (22HQ) and pin AD/9E of the SDAC-1 (1WV1)
. Pin A/M of the skin air-outlet valve (22HQ) and pin AD/9E of the SDAC-2 (1WV2)
. Pin A/R of the skin air-outlet valve (22HQ) and pin AD/10D of the SDAC-1 (1WV1)
. Pin A/R of the skin air-outlet valve (22HQ) and pin AD/10D of the SDAC-2 (1WV2).

(3) If the fault continues and if the test gives the maintenance message SKIN AIR INLET V 15HQ:

Replace the VALVE-SKIN AIR INLET, AVNCS VENT [15HQ] AMM 21-26-52-000-001 and AMM 21-26-52-400-001.

(4) If the fault continues and if the test gives the maintenance message SKIN AIR OUTLET V 22HQ:

Replace the VALVE-SKIN AIR OUTLET, AVNCS VENT [22HQ] AMM 21-26-53-000-002 and AMM 21-26-53-400-001.

[Rev.8 from Aug 2018] 2026.04.04 04:24:39 UTC