LH Wing Loop A Inoperative

TASK 36-22-00-810-836-A
LH Wing Loop A Inoperative

1. Possible Causes

wiring
BMC-1 [1HA1]
CABLE-CONNECTING, L WING LOOP A [21HF]
SNSG ELEM-OVHT, L WING LOOP A [81HF]
SNSG ELEM-OVHT, L WING LOOP A [22HF]
SNSG ELEM-OVHT, L WING LOOP A [23HF]
CABLE-CONNECTING, L WING LOOP A [24HF]
CABLE-CONNECTING, L WING LOOP A [25HF]
SNSG ELEM-OVHT, L WING LOOP A [26HF]
SNSG ELEM-OVHT, L WING LOOP A [27HF]
SNSG ELEM-OVHT, L WING LOOP A [28HF]
SNSG ELEM-OVHT, L WING LOOP A [29HF]
INTERCONNECTING CABLE [90HF]
OVHT SENS ELEMENT [73HF]
OVHT SENS ELEMENT [31HF]
OVERHEAT SENSING ELEM [32HF]
OVHT SENS ELEMENT [33HF]
OVHT SENS ELEMENT [34HF]
OVHT SENS ELEMENT [35HF]
OVHT SENS ELEMENT [36HF]
CABLE ASSY [30HF]

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

REFERENCE	QTY	DESIGNATION
9240SI	1	CONTROLLER-LOOP

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 36-22-00-810-875-A	Leak Detection from the Loop A in the Left Wing
ESPM 204422
AMM 36-11-00-740-802	BITE Test of the Engine Bleed Air System (EBAS) (System Test)
AMM 36-11-34-000-001	Removal of the BMC
AMM 36-11-34-400-001	Installation of the BMC
AMM 36-22-00-100-803	Clean the Overheat Detection System (OHDS) Connectors and Apply the Electrical Insulating Compound
ASM 362201
AWM 362201
AMM 36-22-16-000-001	Removal of the Overheat Sensing Elements
AMM 36-22-16-000-002	Removal of the Cables
AMM 36-22-16-000-003	Removal of the Cables
AMM 36-22-16-000-004	Removal of the Overheat Sensing Elements
AMM 36-22-16-000-005	Removal of the Overheat Sensing Elements
AMM 36-22-16-000-006	Removal of the Overheat Sensing Elements
AMM 36-22-16-000-007	Removal of the Cables
AMM 36-22-16-400-001	Installation of the Overheat Sensing Elements
AMM 36-22-16-400-002	Installation of the Cables
AMM 36-22-16-400-003	Installation of the Cables
AMM 36-22-16-400-004	Installation of the Overheat Sensing Elements
AMM 36-22-16-400-005	Installation of the Overheat Sensing Elements
AMM 36-22-16-400-007	Installation of the Overheat Sensing Elements
AMM 36-22-16-400-008	Installation of the Cables

3. Fault Confirmation
Subtask 36-22-00-740-051-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test AMM 36-11-00-740-802.

4. Fault Isolation
Subtask 36-22-00-810-093-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message L WING LOOP A INOP or L WING LOOP A OPEN:

NOTE: This procedure is applicable when there is a loss of the LH wing loop-A detection-signal or to the incorrect continuity of the loop.

Remove BMC-1 AMM 36-11-34-000-001.
On shelf 95VU, connect the 9240SI CONTROLLER-LOOP between BMC-1 pin AA/4G and AA/5G ASM 362201.
Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:

(1) If the continuity resistance value is less than 16.5 Ohms:

On shelf 95VU, connect the 9240SI CONTROLLER-LOOP between connector BMC-1 pin AA/4G and the ground ASM 362201.
Do a check of the insulation resistance shown on the 9240SI CONTROLLER-LOOP.

(a) If the insulation resistance is more than 10 kOhms:

Go to Para. 4.B.

(b) If the insulation resistance is less than 10 kOhms:

Do the fault isolation steps (Ref. TSM TASK 36-22-00-810-875).

(2) If the continuity resistance value is more than 16.5 Ohms

Connect the 9240SI CONTROLLER-LOOP between connector 1907VC pin A/38 to connector 1969VC pin A/22 AWM 362201.

(a) If the continuity resistance value is more than 16.5 Ohms:

Do a visual inspection of the sensing elements and the connecting cables on LH wing loop A.

1 If a sensing element or a connecting cable is damaged:

Disconnect the 9240SI CONTROLLER-LOOP from connector 1907VC pin A/38 to connector 1969VC pin A/22.
Replace the defective sensing element or connecting cable
AMM 36-22-16-000-001 and AMM 36-22-16-400-001,
AMM 36-22-16-000-002 and AMM 36-22-16-400-002,
AMM 36-22-16-000-003 and AMM 36-22-16-400-003,
AMM 36-22-16-000-007 and AMM 36-22-16-400-008,
AMM 36-22-16-000-004 and AMM 36-22-16-400-004,
AMM 36-22-16-000-005 and AMM 36-22-16-400-005 and
AMM 36-22-16-000-006 and AMM 36-22-16-400-007.
Install BMC-1 AMM 36-11-34-400-001.

2 If no sensing element or connecting cable is damaged:

Go to Para. 4.B.

(b) If the continuity resistance value is less than 16.5 Ohms:

Connect the 9240SI CONTROLLER-LOOP between connector 1907VC pin A/38 and BMC-1 pin AA/4G AWM 362201.

1 If the continuity resistance value is more than 16.5 Ohms:

Disconnect the 9240SI CONTROLLER-LOOP from connector 1907VC pin A/38 and BMC-1 pin AA/4G.
Repair or replace the wiring ESPM 204422.
Install BMC-1 AMM 36-11-34-400-001.

2 If the continuity resistance value is less than 16.5 Ohms:

Connect the 9240SI CONTROLLER-LOOP between connector 1969VC pin A/22 and BMC-1 pin AA/5G AWM 362201.

a If the continuity resistance value is more than 16.5 Ohms:

Repair or replace the wiring ESPM 204422.
Install BMC-1 AMM 36-11-34-400-001.

b If the continuity resistance value is less than 16.5 Ohms:

Do the cleaning procedure AMM 36-22-00-100-803.
Do the BITE test of the EBAS AMM 36-11-00-740-802.
* If the fault continues:
** Replace BMC-1 [1HA1] AMM 36-11-34-000-001 and AMM 36-11-34-400-001.

Subtask 36-22-00-810-205-A ** ON A/C NOT FOR ALL

B. Dichotomy Procedure

NOTE: The purpose of this procedure is to find and isolate the elements that causes a high continuity resistance on loop-A of the LH wing.

(1) Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
(a) If the continuity resistance value is more than 16.5 Ohms:

Disconnect the connecting cable (21HF) of connector 1907VC pin A/38 and the connecting cable (30HF) of the connector 1969VC pin A/22 AMM 36-22-16-000-002. Disconnect one after the other all the sensing elements between the connection cables (21HF) and (30HF) AMM 36-22-16-000-001, AMM 36-22-16-000-003, AMM 36-22-16-000-007, AMM 36-22-16-000-004, AMM 36-22-16-000-005 and AMM 36-22-16-000-006.
Measure the continuity resistance with the 9240SI CONTROLLER-LOOP between the center pin on the two ends of each of the elements.
Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:

1 If the continuity resistance value is more than 16.5 Ohms:

Disconnect the 9240SI CONTROLLER-LOOP.
Replace the defective elements:
CABLE-CONNECTING, L WING LOOP A [21HF] or
SNSG ELEM-OVHT, L WING LOOP A [81HF] or
SNSG ELEM-OVHT, L WING LOOP A [22HF] or
SNSG ELEM-OVHT, L WING LOOP A [23HF] or
CABLE-CONNECTING, L WING LOOP A [24HF] or
CABLE-CONNECTING, L WING LOOP A [25HF] or
SNSG ELEM-OVHT, L WING LOOP A [26HF] or
SNSG ELEM-OVHT, L WING LOOP A [27HF] or
SNSG ELEM-OVHT, L WING LOOP A [28HF] or
SNSG ELEM-OVHT, L WING LOOP A [29HF] or
INTERCONNECTING CABLE [90HF] or
OVHT SENS ELEMENT [73HF] or
OVHT SENS ELEMENT [31HF] or
OVERHEAT SENSING ELEM [32HF] or
OVHT SENS ELEMENT [33HF] or
OVHT SENS ELEMENT [34HF] or
OVHT SENS ELEMENT [35HF] or
OVHT SENS ELEMENT [36HF] or
CABLE ASSY [30HF]
AMM 36-22-16-000-001 and AMM 36-22-16-400-001,
AMM 36-22-16-000-002 and AMM 36-22-16-400-002,
AMM 36-22-16-000-003 and AMM 36-22-16-400-003,
AMM 36-22-16-000-007 and AMM 36-22-16-400-008,
AMM 36-22-16-000-004 and AMM 36-22-16-400-004,
AMM 36-22-16-000-005 and AMM 36-22-16-400-005 and
AMM 36-22-16-000-006 and AMM 36-22-16-400-007.
Install BMC-1 AMM 36-11-34-400-001.

2 If the continuity resistance value is less than 16.5 Ohms:

Disconnect the 9240SI CONTROLLER-LOOP.
Clean all the connections of the sensing elements and the connecting cables to remove contamination and decrease the resistance of the loop AMM 36-22-00-100-803 AWM 362201.
Connect again all the sensing elements or connecting cables disconnected AMM 36-22-16-400-001, AMM 36-22-16-400-002, AMM 36-22-16-400-003, AMM 36-22-16-400-008, AMM 36-22-16-400-004, AMM 36-22-16-400-005 and AMM 36-22-16-400-007.
Install BMC-1 AMM 36-11-34-400-001.

(b) If the continuity resistance value is less than 16.5 Ohms:

Disconnect the 9240SI CONTROLLER-LOOP.
Connect again all the sensing elements or connecting cables disconnected AMM 36-22-16-400-001, AMM 36-22-16-400-002, AMM 36-22-16-400-003, AMM 36-22-16-400-008, AMM 36-22-16-400-004, AMM 36-22-16-400-005 and AMM 36-22-16-400-007.
Replace BMC-1 [1HA1] AMM 36-11-34-000-001 and AMM 36-11-34-400-001.

[Rev.8 from Aug 2018] 2026.04.04 04:40:32 UTC