Blower Fan Inoperative because of a Failure of the AEVC

TASK 21-26-00-810-813-A
Blower Fan Inoperative because of 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)
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System

3. Fault Confirmation
Subtask 21-26-00-865-056-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FWS/FWC1/SPLY	3WW	F01
121VU	EIS/FWC2/SPLY	2WW	Q07
122VU	AIR COND/AVNCS/VENT/MONG	3HQ	Y17

Subtask 21-26-00-710-077-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 21-26-00-810-064-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 A/E of the avionics-ventilation blower fan (20HQ)
. Pin A/D of the avionics-ventilation blower fan (20HQ) and pin X of the avionics-ventilation blower-fan contactor (8HQ)
. Pin Z of the avionics-ventilation blower-fan contactor (8HQ) and pin AA/8A of the AEVC (10HQ).

Subtask 21-26-00-710-113-A

B. Test
(1) Reset of the FWC1 and FWC2

NOTE: The circuit breakers must be open for a minimum of five seconds before you close them.

(a) Open this(these) circuit breaker(s):
1 2WW
2 3WW.
(b) Close this(these) circuit breaker(s):
1 2WW
2 3WW.
(2) Do the ground scanning of the central warning system AMM 31-50-00-710-001.

[Rev.8 from Aug 2018] 2026.04.04 04:24:37 UTC