Engine 2 Pylon Loop A Inoperative
TASK 36-22-00-810-834-A
Engine 2 Pylon Loop A Inoperative
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 36-22-00-740-050-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 36-22-00-810-092-B ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:34:06 UTC
Engine 2 Pylon Loop A Inoperative
1. Possible Causes
- wiring
- BMC-1 [1HA1]
- SNSG ELEM-OVHT, ENG 2 PYLON [1HF2]
- CABLE-CONNECTING, ENG 2 PYLON [2HF2]
- CABLE-CONNECTING, R PYLON LOOP A [4HF2]
- SENSING ELEMENT-OVHT, R PYLON LOOP A [6HF2]
- CABLE ASSY [3HF2]
- CABLE-CONNECTING, R PYLON LOOP A [5HF2]
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| 9240SI | 1 | CONTROLLER-LOOP |
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 36-22-00-810-881-A | Leak Detection of the Engine 2 Pylon Loop A |
| 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 36-22-15-000-802 | Removal of the Pylon Overheat Sensing-Elements |
| AMM 36-22-15-000-803 | Removal of the Pylon Overheat Sensing-Elements |
| AMM 36-22-15-400-802 | Installation of the Pylon Overheat Sensing-Elements |
| AMM 36-22-15-400-803 | Installation of the Pylon Overheat Sensing-Elements |
Subtask 36-22-00-740-050-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 36-22-00-810-092-B ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message ENG2 PYLON LOOP A INOP or ENG2 PYLON LOOP A OPEN:
Subtask 36-22-00-810-203-A ** ON A/C NOT FOR ALL NOTE: This procedure is applicable when there is a loss of the engine-2 pylon 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/4D and AA/5D ASM 362201.
- Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
- On shelf 95VU, connect the 9240SI CONTROLLER-LOOP between connector BMC-1 pin AA/4D and the ground ASM 362201.
- Do a check of the insulation resistance shown on the 9240SI CONTROLLER-LOOP.
- Go to Para. 4.B.
- Do the fault isolation steps (Ref. TSM TASK 36-22-00-810-881).
- Connect the 9240SI CONTROLLER-LOOP between connector 422VC pin A/2 to A/3 AWM 362201.
- Do a visual inspection of the sensing elements and the connecting cables on engine 2 pylon loop A.
- Disconnect the 9240SI CONTROLLER-LOOP from 422VC connector pin A/2 to A/3.
- Replace the defective sensing element or connecting cable AMM 36-22-15-000-802 and AMM 36-22-15-400-802, AMM 36-22-15-000-803 and AMM 36-22-15-400-803.
- Install BMC-1 AMM 36-11-34-400-001.
- Go to Para. 4.B.
- Connect the 9240SI CONTROLLER-LOOP between connector 422VC pin A/2 and BMC-1 pin AA/4D AWM 362201.
- Disconnect the 9240SI CONTROLLER-LOOP from connector 422VC pin A/2 and BMC-1 pin AA/4D.
- Repair or replace the wiring ESPM 204422.
- Install BMC-1 AMM 36-11-34-400-001.
- Connect the 9240SI CONTROLLER-LOOP between connector 422VC pin A/3 and BMC-1 pin AA/5D AWM 362201.
- Repair or replace the wiring ESPM 204422.
- Install BMC-1 AMM 36-11-34-400-001.
- 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.
B. Dichotomy Procedure
(2) Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
(a) If the continuity resistance value is more than 8 Ohms:
NOTE: The purpose of this procedure is to find and isolate the element that causes a high continuity resistance on loop-A of the engine-2 pylon.
(1) Connect the 9240SI CONTROLLER-LOOP between connector 422VC pin A/2 to terminal block 450VT2 pin 6/A AWM 362201. (2) Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
(a) If the continuity resistance value is more than 8 Ohms:
- Disconnect the sensing element (1HF2) from connecting cables (2HF2) and (4HF2) AMM 36-22-15-000-803.
- Measure the continuity resistance with the 9240SI CONTROLLER-LOOP between the center pin on the two ends of each of the sensing element.
- Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
- Disconnect the 9240SI CONTROLLER-LOOP.
- Replace the defective SNSG ELEM-OVHT, ENG 2 PYLON [1HF2] or CABLE-CONNECTING, ENG 2 PYLON [2HF2] or CABLE-CONNECTING, R PYLON LOOP A [4HF2] AMM 36-22-15-000-803 and AMM 36-22-15-400-803.
- Install BMC-1 AMM 36-11-34-400-001.
- Disconnect the 9240SI CONTROLLER-LOOP.
- Clean all the connections of sensing element (1HF2) and connecting cables (2HF2) and (4HF2) to remove contamination and decrease the resistance of the loop AMM 36-22-00-100-803 AWM 362201.
- Intall the sensing elemment (1HF2) AMM 36-22-15-400-803.
- Install BMC-1 AMM 36-11-34-400-001.
- Connect the 9240SI CONTROLLER-LOOP between connector 422VC pin A/3 to terminal block 450VT2 pin 6/B AWM 362201.
- Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
- Disconnect the sensing element (6HF2) from connecting cables (3HF2) and (5HF2) AMM 36-22-15-000-802.
- Measure the continuity resistance with the 9240SI CONTROLLER-LOOP between the center pin on the two ends of each of the sensing elements.
- Do a check of the continuity resistance shown on the 9240SI CONTROLLER-LOOP:
- Disconnect the 9240SI CONTROLLER-LOOP.
- Replace the defective SENSING ELEMENT-OVHT, R PYLON LOOP A [6HF2] or CABLE ASSY [3HF2] or CABLE-CONNECTING, R PYLON LOOP A [5HF2] AMM 36-22-15-000-802 and AMM 36-22-15-400-802.
- Install BMC-1 AMM 36-11-34-400-001.
- Disconnect the 9240SI CONTROLLER-LOOP.
- Clean all the connections of sensing element (6HF2) and connecting cables (3HF2) and (5HF2) to remove contamination and decrease the resistance of the loop AMM 36-22-00-100-803 AWM 362201.
- Install the sensing element (6HF2) AMM 36-22-15-400-802.
- Install BMC-1 AMM 36-11-34-400-001.
- Disconnect the 9240SI CONTROLLER-LOOP.
- Connect again all the sensing elements or connecting cables disconnected AMM 36-22-15-400-802.
- Replace BMC-1 [1HA1] AMM 36-11-34-000-001 and AMM 36-11-34-400-001.