Air Leak in the Engine 1 Pylon

TASK 36-22-00-810-803-A
Air Leak in the Engine 1 Pylon

1. Possible Causes

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
9240SI	1	CONTROLLER-LOOP

B. Referenced Information

REFERENCE	DESIGNATION
AMM 24-92-00-220-001	Detailed Inspection of EWIS Installed in the Upper Forward Pylon (EWIS)
AMM 36-11-34-000-001	Removal of the BMC
AMM 36-11-34-400-001	Installation of the BMC
ASM 362201
AMM 36-22-15-000-001	Removal of the Pylon Overheat Sensing-Element
AMM 36-22-15-400-001	Installation of the Pylon Overheat Sensing-Element

3. Fault Confirmation
Subtask 36-22-00-720-052-A ** ON A/C NOT FOR ALL

A. Test
(1) Start the APU.
(2) On the AIR control panel 30VU, push the APU BLEED pushbutton switch.

4. Fault Isolation
Subtask 36-22-00-810-052-A ** ON A/C NOT FOR ALL

A. If the ground report gives the maintenance message ENG 1 PYLON LEAK:

(1) If the duct is cracked/damaged:

(2) If there are leaks on the seals:

NOTE: If there are no air leaks, replace the seals (to prevent leaks).

(3) Do a visual inspection of the wiring installed in the left forward pylon AMM 24-92-00-220-001.

Subtask 36-22-00-810-088-A ** ON A/C NOT FOR ALL

B. If no leak warning comes into view:

remove the BMC1 (1HA1) AMM 36-11-34-000-001.
on the shelf 95VU, connect the 9240SI CONTROLLER-LOOP between the connector 1HA1-AA/5B and the ground ASM 362201
do a check of the impedance read on the 9240SI CONTROLLER-LOOP.

(1) If the impedance is more than 17 KOhms:

disconnect the 9240SI CONTROLLER-LOOP from the BMC1 connector
replace the BMC-1 [1HA1] which is removed AMM 36-11-34-000-001 and AMM 36-11-34-400-001.
refer to Para. 4.C.

(2) If the impedance is less than 17 KOhms:

disconnect the 9240SI CONTROLLER-LOOP from the BMC1 connector
do a visual inspection of the sensing elements and cables on the engine 1 pylon loop.

(a) If a sensing element or cable is damaged:

replace the sensing element or cable AMM 36-22-15-000-001 and AMM 36-22-15-400-001
disconnect the 9240SI CONTROLLER-LOOP from the BMC1 connector
install the BMC1 AMM 36-11-34-400-001
refer to Para. 4.C.

(b) If no sensing element is damaged:

disconnect the connector between the cable 2HF1 and the sensing element 1HF1
connect the 9240SI CONTROLLER-LOOP between the connector 1HA1-AA/5B and the ground
do a check of the impedance read on the 9240SI CONTROLLER-LOOP.

1 If the impedance is less than 17 KOhms:

replace the CABLE-CONNECTING, ENG 1 PYLON [2HF1] AMM 36-22-15-000-001 and AMM 36-22-15-400-001
do a check of the impedance read on the 9240SI CONTROLLER-LOOP.

a If the impedance is less than 17 KOhms:

do a check and repair the wiring between the pin 5B of the BMC1 connector (1HA1-AA) and the cable 2HF1
connect all the cables or connectors disconnected
disconnect the 9240SI CONTROLLER-LOOP from the BMC1 connector
install the BMC1 (1HA1) AMM 36-11-34-400-001
refer to Para. 4.C.

b If the impedance is more than 17 KOhms:

2 If the impedance is more than 17 KOhms:

a If the impedance is less than 302 KOhms:

replace the SNSG ELEM-OVHT, ENG 1 PYLON [1HF1]
disconnect the 9240SI CONTROLLER-LOOP from the BMC connector
install the BMC-1 [1HA1] which is removed AMM 36-11-34-400-001
- refer to Para. 4.C.

b If the impedance is more than 302 KOhms:

Subtask 36-22-00-700-052-A ** ON A/C NOT FOR ALL

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

[Rev.8 from Aug 2018] 2026.04.04 04:40:29 UTC