Aft Trim Air Pressure Regulating Valve (TAPRV) Control Circuit Fault

TASK 21-43-00-810-820-A
Aft Trim Air Pressure Regulating Valve (TAPRV) Control Circuit Fault

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 214302
AMM 21-61-00-710-001	Operational Test of the Pack Temperature-Control System

3. Fault Confirmation
Subtask 21-43-00-710-086-A ** ON A/C NOT FOR ALL

A. Do the operational test of the pack temperature-control system AMM 21-61-00-710-001.

NOTE: The ZC (8HK) also monitors the cargo compartment heating system.

Subtask 21-43-00-710-086-D ** ON A/C NOT FOR ALL

A. Do the operational test of the pack temperature-control system AMM 21-61-00-710-001.

4. Fault Isolation
Subtask 21-43-00-810-078-A

A. If the test gives the maintenance message AFT TAPRV SHUT OFF RELAY:

do a check for the RELAY-TAPRV CLOSE (17HC) and replace it if necessary ASM 214302.

(1) If the fault continues:

do a check for the PUSHBUTTON SWITCH-CARGO HEAT/HOT AIR (16HC) and replace it if necessary ASM 214302.

(2) If the fault continues:

do a check and repair the wiring between:
the ACHC (10HC) AA/6A and CB (31HN) ASM 214302.

Subtask 21-43-00-710-087-A

B. Do the test given in Para. 3.

5. Close-up
Subtask 21-43-00-860-067-A

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:24:46 UTC