Altitude Pressure Switch Failure

TASK 38-31-00-810-808-A
Altitude Pressure Switch Failure

1. Possible Causes

SWITCH,ALTITUDE PRESS [43MG]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 38-31-00-710-009	Operational Test of the Toilet Unit
AMM 38-31-00-740-001	BITE Test of the Vacuum Toilet System
AMM 38-31-69-000-001	Removal of the Altitude Pressure Switch
AMM 38-31-69-400-001	Installation of the Altitude Pressure Switch
MCDU Display

3. Fault Confirmation
Subtask 38-31-00-710-057-A ** ON A/C NOT FOR ALL

A. Test
(1) Do a test of the vacuum toilet system AMM 38-31-00-710-009.

Subtask 38-31-00-740-058-A ** ON A/C NOT FOR ALL

B. Do the bite test AMM 38-31-00-740-001.

4. Fault Isolation
Subtask 38-31-00-810-057-B ** ON A/C NOT FOR ALL

A. If the operational test operates OK:

Refer to the bite test last leg or previous legs report.

(1) If the LAST LEG REPORT or PREVIOUS LEGS REPORT gives the maintenance message ALT PRESS SW:

MCDU Display ** ON A/C NOT FOR ALL

(2) do a check of the electrical connections 43MG/A.
(3) If the electrical connections are ok:

replace the SWITCH,ALTITUDE PRESS [43MG] , AMM 38-31-69-000-001 and AMM 38-31-69-400-001.

NOTE: If the altitude pressure switch does not operate, the system will continue to operate as follows:

the LG signal is used to give the information ON GROUND or IN FLIGHT
on the ground the vacuum generator will operate,
in flight the vacuum generator is inhibited.

Subtask 38-31-00-710-069-A ** ON A/C NOT FOR ALL

B. Test
(1) Do the test given as in paragraph 3. A. to check the correct operation AMM 38-31-00-710-009.
(2) After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:34:13 UTC