Vacuum Waste Line Failure

TASK 38-31-00-810-857-A
Vacuum Waste Line Failure

1. Possible Causes

blockages at the flush valve
blockages of the waste line

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 38-30-00-010-002	Removal of the Toilet Drain Lines
AMM 38-30-00-410-002	Installation of the Toilet Drain Lines
AMM 38-30-00-615-002	Blockage Removal (Orbital Flush Valve)
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
MCDU Display ** ON A/C NOT FOR ALL
MCDU Display ** ON A/C NOT FOR ALL

3. Fault Confirmation
Subtask 38-31-00-710-161-A

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

Subtask 38-31-00-740-087-A

B. Do the procedure to get access to the CFDS SYSTEM REPORT/TEST menu PAGE AMM 38-31-00-740-001.

4. Fault Isolation
Subtask 38-31-00-810-161-A

A. If the LAST/PREVIOUS LEGS Report gives the maintenance message
TOILET ASSY LAV X:
(1) Do a check of the related toilet assembly and make sure that there are no blockages at the flush valve AMM 38-30-00-615-002.
(2) Flush the toilet.
(3) If the toilet flushes correctly, do a flush cycle at the forward toilet assemblies.
(4) Do a check of the vacuum flow.
(5) If the toilets flush correctly, do a flush cycle at the aft toilet assemblies.
(6) Do a check of the vacuum flow.
(7) If the toilets flush incorrectly, do the procedure that follows:

NOTE: This procedure helps to locate the blockages of the waste line more accurately.

(a) Remove the shroud of the toilet that did not flush correctly:

Push the toilet flush switch.
Make sure that the flush valve is open and disconnect the plug from the flush control unit.
Put a flexible water hose into the toilet until it is stopped by a blockage.
Make marks on the hose to show its length.
Remove the hose from the toilet.

NOTE: Make sure that no waste comes out of the toilet on the hose. If necessary, clean the hose with a cloth while you remove it.

With the length of the hose, the position of the blockage can be identified.
Discard the hose after this procedure.

(b) Find the clogged pipe located aft of the identified toilet assembly.
(c) Remove the clogged pipe AMM 38-30-00-010-002.

NOTE: Make sure that no waste falls out of the pipe onto the aircraft.

(d) Remove the blockage in the workshop.
(e) Install the pipe AMM 38-30-00-410-002.

Subtask 38-31-00-710-162-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:34:16 UTC