Fuel Found in the Stack Pipes above the ACT Pressurization Points T1 #amp# T2

TASK 28-11-00-810-815-A
Fuel Found in the Stack Pipes above the ACT Pressurization Points T1 & T2

1. Possible Causes

CHECK VALVE-ACT PRESSURIZATION [178QM]
CHECK VALVE-ACT PRESSURIZATION [177QM1]
CHECK VALVE-ACT2 [177QM2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 28-28-00-720-005	Functional Test of the Check Valves of the ACT (177QM)
AMM 28-28-37-000-001	Removal of the Air Inlet Check Valve (177QM)
AMM 28-28-37-400-001	Installation of the Air Inlet Check Valve (177QM)
AMM 28-28-38-000-002	Removal of the ACT Pressurization Check Valve
AMM 28-28-38-400-002	Installation of the ACT Pressurization Check Valve

3. Fault Confirmation

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

Subtask 28-11-00-710-067-A ** ON A/C NOT FOR ALL

A. Test
(1) No test is applicable.

4. Fault Isolation
Subtask 28-11-00-810-064-A ** ON A/C NOT FOR ALL

A. Procedure
(1) If you find fuel on the test ports T1 or T2:
(a) Replace the CHECK VALVE-ACT PRESSURIZATION [178QM] AMM 28-28-38-000-002 and AMM 28-28-38-400-002.
(2) Do the Functional Test of the check valves of the ACT (177QM) AMM 28-28-00-720-005.
(a) If the test of the of check valve 177QM1 of the ACT1 is not satisfactory:

replace the CHECK VALVE-ACT PRESSURIZATION [177QM1] AMM 28-28-37-000-001 and AMM 28-28-37-400-001.

(b) If the test of the check valve 177QM2 of the ACT2 is not satisfactory:

replace the CHECK VALVE-ACT2 [177QM2] AMM 28-28-37-000-001 and AMM 28-28-37-400-001.

(3) Continue with your original AMM/TSM task or, if applicable, return the aircraft to service.

[Rev.8 from Aug 2018] 2026.04.04 04:28:27 UTC