DOC AIRBUS | AMM A320FInsulation Resistance and Shorted Wire Checks - All Power Plant Electrical Cables [IAE]
TASK 71-50-00-220-011-A
Insulation Resistance and Shorted Wire Checks - All Power Plant Electrical Cables
1. Reason for the Job
This procedure is applicable to all power plant electrical cables. This procedure provides the information necessary to accomplish an insulation resistance check and a shorted wire check.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 71-50-00-941-055-A ** ON A/C NOT FOR ALL
Subtask 71-50-00-020-051-A ** ON A/C NOT FOR ALL
Subtask 71-50-00-410-058-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 02:30:37 UTC
Insulation Resistance and Shorted Wire Checks - All Power Plant Electrical Cables
1. Reason for the Job
This procedure is applicable to all power plant electrical cables. This procedure provides the information necessary to accomplish an insulation resistance check and a shorted wire check.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | MEGOHMMETER - MODEL 1863 |
| No specific | AR | WARNING NOTICE(S) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| FOR [1000EM1] (ENGINE-1) | |
| 437AL, 438AR, 451AL, 452AR | |
| FOR [1000EM2] (ENGINE-2) | |
| 447AL, 448AR, 461AL, 462AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-13-00-010-010-A | Opening of the Fan Cowls 437AL(447AL),438AR(448AR) |
| TASK 71-13-00-410-010-A | Closing of the Fan Cowls 437AL(447AL),438AR(448AR) |
| TASK 78-30-00-040-012-A | Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance |
| TASK 78-30-00-440-012-A | Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after Ground Maintenance |
| TASK 78-32-00-010-010-A | Opening of the Thrust Reverser Halves |
| TASK 78-32-00-410-010-A | Closing of the Thrust Reverser Halves |
Subtask 71-50-00-941-055-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
Subtask 71-50-00-010-058-A ** ON A/C NOT FOR ALL (1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
B. Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR.
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
Subtask 71-50-00-040-055-A ** ON A/C NOT FOR ALL (1) FOR [1000EM1] (ENGINE-1)
437AL 438AR.
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
C. Deactivate the thrust reverser.
Subtask 71-50-00-010-061-A ** ON A/C NOT FOR ALL WARNING:
MAKE SURE THAT THE THRUST REVERSER HYDRAULIC CONTROL UNIT (HCU) IS DEACTIVATED BEFORE YOU DO WORK ON OR AROUND THE THRUST REVERSER. IF THE HCU IS NOT DEACTIVATED, THERE IS A RISK OF UNWANTED THRUST REVERSER OPERATION WHICH CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.
(1) Deactivate the thrust reverser hydraulic control unit (HCU) (Ref. AMM TASK 78-30-00-040-012). D. Open the thrust reverser halves (Ref. AMM TASK 78-32-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR.
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
4. Procedure(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR.
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
Subtask 71-50-00-020-051-A ** ON A/C NOT FOR ALL
A. Disconnect the two connectors of the wire harness which contains the cable of the circuit to be checked.
Subtask 71-50-00-220-051-A ** ON A/C NOT FOR ALL B. Shorted wire Check and Insulation Resistance Check:
(a) Do the shorted wire check on the suspect wire. Use a MEGOHMMETER - MODEL 1863 or equivalent.
(b) Set the megohmmeter to the 100 volt DC scale.
1 Check the resistance between each pair of wires which are suspect.
2 The resistance must be infinity.
3 Defective circuits must be repaired (ref. AMM 70-71-00 pb 001).
(2) Insulation resistance check:
(a) Do the insulation resistance check on the suspect circuit. Use a MEGOHMMETER - MODEL 1863 or equivalent.
(b) Set the megohmmeter to the 500 volt DC scale.
1 Connect one test lead of the megohmmeter to the backshell body of the connector. Connect the other test lead to the contact (pin or socket) of the connector.
2 Measure the insulation resistance.
3 The resistance must be a minimum of 20 megohms.
4 Defective circuits must be repaired (ref. AMM 70-71-00 pb 001).
Subtask 71-50-00-420-051-A ** ON A/C NOT FOR ALL CAUTION:
DO NOT CAUSE DAMAGE TO CONNECTOR PINS WHEN YOU DO CONTINUITY CHECKS. DAMAGED PINS CAN BECOME LOOSE AND CAN THUS INTERMITTENTLY PREVENT CORRECT CONTINUITY.
(1) Shorted wire check. (a) Do the shorted wire check on the suspect wire. Use a MEGOHMMETER - MODEL 1863 or equivalent.
(b) Set the megohmmeter to the 100 volt DC scale.
1 Check the resistance between each pair of wires which are suspect.
2 The resistance must be infinity.
3 Defective circuits must be repaired (ref. AMM 70-71-00 pb 001).
(2) Insulation resistance check:
(a) Do the insulation resistance check on the suspect circuit. Use a MEGOHMMETER - MODEL 1863 or equivalent.
(b) Set the megohmmeter to the 500 volt DC scale.
1 Connect one test lead of the megohmmeter to the backshell body of the connector. Connect the other test lead to the contact (pin or socket) of the connector.
2 Measure the insulation resistance.
3 The resistance must be a minimum of 20 megohms.
4 Defective circuits must be repaired (ref. AMM 70-71-00 pb 001).
C. Connect all the connectors and secure.
5. Close-upSubtask 71-50-00-410-058-A ** ON A/C NOT FOR ALL
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser halves (Ref. AMM TASK 78-32-00-410-010):
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR.
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
Subtask 71-50-00-440-055-A ** ON A/C NOT FOR ALL Subtask 71-50-00-410-061-A ** ON A/C NOT FOR ALL (1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser halves (Ref. AMM TASK 78-32-00-410-010):
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR.
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR.