Outflow Valve Fault (33) (81)

TASK 21-31-00-810-828-A
Outflow Valve Fault (33) (81)

1. Possible Causes

OUTFLOW VALVE [10HL]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 21-31-51-000-001	Removal of the Outflow Valve (From Inside)
AMM 21-31-51-000-006	Removal of the Outflow Valve (From Outside)
AMM 21-31-51-400-001	Installation of the Outflow Valve (From Inside)
AMM 21-31-51-400-006	Installation of the Outflow Valve (From Outside)
AMM 38-32-00-790-001	Leak Test of the Waste/Water Drain System

3. Fault Confirmation
Subtask 21-31-00-710-104-A

A. The fault cannot be reproduced on the ground.

4. Fault Isolation
Subtask 21-31-00-810-178-A ** ON A/C NOT FOR ALL

A. If one or both of the reports, LAST LEG REPORT, PREVIOUS LEG REPORT gives the maintenance messages OUTFLOW VALVE (33) and/or OUTFLOW VALVE (81):
(1) Do a visual inspection of the outflow valve (10HL) mechanism body for ice or water. If ice or water is found on the outflow valve:

remove the ice or water and dry the area.
do a check of the waste/water drain system for leakages AMM 38-32-00-790-001.

(2) If no ice or water is found on the outflow valve:

replace the OUTFLOW VALVE [10HL]
AMM 21-31-51-000-001 and
AMM 21-31-51-400-001 or
AMM 21-31-51-000-006 and
AMM 21-31-51-400-006.

NOTE: It is necessary to do the tests of the Pressure Control and Monitoring System on the two system channels at the end of the installation procedure.

After the subsequent flight, make sure that the fault does not continue.

Subtask 21-31-00-810-178-B ** ON A/C NOT FOR ALL

remove the ice or water and dry the area.
do a check of the waste/water drain system for leakages AMM 38-32-00-790-001.

(2) If no ice or water is found on the outflow valve:

replace the OUTFLOW VALVE [10HL]
AMM 21-31-51-000-001 and
AMM 21-31-51-400-001.

NOTE: It is necessary to do the tests of the Pressure Control and Monitoring System on the two system channels at the end of the installation procedure.

After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:24:43 UTC