Blower Fan and Extract Fan Inoperative due to a Failure of the AEVC

TASK 21-26-00-810-845-A
Blower Fan and Extract Fan Inoperative due to a Failure of the AEVC

1. Possible Causes

AEVC [10HQ]
wiring

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 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)

3. Fault Confirmation
Subtask 21-26-00-865-074-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 21-26-00-710-116-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 21-26-00-810-095-A

A. If the test gives the maintenance message AEVC:

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

(1) If the fault continues:

Do a check and repair the wiring ASM 212603 between pin 2 of the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ) and pin AA/1A of the AEVC (10HQ).

Subtask 21-26-00-710-128-A

B. Do the test given in Para. 3.

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