Loss of the Leak Detection Loop on the Engine 1 Pylon

TASK 36-22-00-810-810-A
Loss of the Leak Detection Loop on the Engine 1 Pylon

1. Possible Causes

BMC-1 [1HA1]
wiring
SNSG ELEM-OVHT, ENG 1 PYLON [1HF1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 36-11-00-740-001	BITE Test of the BMC 1(2)
AMM 36-11-34-000-001	Removal of the BMC
AMM 36-11-34-400-001	Installation of the BMC
AMM 36-22-00-100-801	Clean the Overheat Detection System (OHDS) Connectors and Apply the Electrical Insulating Compound
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 36-22-00-710-058-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test of the BMC1 AMM 36-11-00-740-001.

4. Fault Isolation
Subtask 36-22-00-810-059-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:
ENG1 PYLON LOOP INOP

remove the BMC-1 [1HA1] AMM 36-11-34-000-001
do a check of the engine 1 pylon-loop from pin AA/5B of the BMC1 to pin AA/6B of the BMC1 ASM 362201.

NOTE: This procedure is related to the loss of the engine 1 pylon-loop detection signal or to incorrect continuity of the loop.
The resistance of the loop must be less than 10 ohms at ambient temperature.
The BMC gives the maintenance message when the resistance of the loop is more than 75 ohms (discontinuity).
There is continuity when the resistance of the loop is less than 75 ohms.

(1) If there is continuity and the resistance of the loop is between 10 ohms and 75 ohms:

do a check and clean all the connections ASM 362201 to remove contamination and decrease the resistance of the loop AMM 36-22-00-100-801.

(a) If the fault continues:

replace the BMC-1 [1HA1] AMM 36-11-34-400-001.

(2) If there is no continuity:

do a check of the wiring from pin AA/5B of the BMC1 to the cable (2HF1) and from pin AA/6B of the BMC1 to the cable (3HF1) ASM 362201.

(a) If there is no continuity:

repair the wiring from pin AA/5B of the BMC1 to the cable (2HF1) and from pin AA/6B of the BMC1 to the cable (3HF1)
install the BMC-1 [1HA1] AMM 36-11-34-400-001.

(b) If there is continuity:

do a check of the sensing element (1HF1).

1 If there is no continuity:

replace the SNSG ELEM-OVHT, ENG 1 PYLON [1HF1] AMM 36-22-15-000-001 and AMM 36-22-15-400-001
install the BMC-1 [1HA1] AMM 36-11-34-400-001.

2 If there is continuity:

do a check and repair the wiring from the connector AA/5B to the sensing element (2HF1) ASM 362201
do a check and repair the wiring from the sensing element (3HF1) to the connector AA/6B ASM 362201
install the BMC-1 [1HA1] AMM 36-11-34-400-001.

Subtask 36-22-00-710-059-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:03 UTC