Downstream NAI Pressure Transducer Signal Failure on Channel A
TASK 30-21-00-810-811-A
Downstream NAI Pressure Transducer Signal Failure on Channel A
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 30-21-00-710-066-A ** ON A/C NOT FOR ALL
Subtask 30-21-00-942-052-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:31 UTC
Downstream NAI Pressure Transducer Signal Failure on Channel A
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | PLIERS - JAWED, SOFT |
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 71-00-00-810-835-A | Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults |
| AMM 30-21-23-000-801 | Removal of the Nacelle Anti-Ice Fan-Pressure-Transducer |
| AMM 30-21-23-400-801 | Installation of the Nacelle Anti-Ice Fan-Pressure-Transducer |
| AMM 71-13-00-010-802 | Opening of the Fan Cowl Doors |
| AMM 71-13-00-410-802 | Closing of the Fan Cowl Doors |
| AWM 715134 | |
| AMM 73-21-00-710-806 | Test No.7 - EEC Operation Test (Self Test) |
| AMM 73-21-01-000-801 | Removal of the Electronic Engine Control (EEC) |
| AMM 73-21-01-400-801 | Installation of the Electronic Engine Control (EEC) |
| AMM 73-21-64-000-802 | Removal of the Electronic Engine Control (EEC) Wiring Harness (W04) |
| AMM 73-21-64-400-802 | Installation of the Electronic Engine Control (EEC) Wiring Harness (W04) |
Subtask 30-21-00-710-066-A ** ON A/C NOT FOR ALL
A. Test
Do the EEC system test AMM 73-21-00-710-806.
(1) If the maintenance message does not come into view again, do the component and harness intermittent for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).
(a) If you find no fault, send the engine back to service and monitor the engine to make sure that the maintenance message does not come into view again.
(2) If the maintenance message comes into view again (hard fault) for Channel A, go to the Para. Fault Isolation.
4. Fault IsolationDo the EEC system test AMM 73-21-00-710-806.
(1) If the maintenance message does not come into view again, do the component and harness intermittent for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).
(a) If you find no fault, send the engine back to service and monitor the engine to make sure that the maintenance message does not come into view again.
(2) If the maintenance message comes into view again (hard fault) for Channel A, go to the Para. Fault Isolation.
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.
CAUTION:
MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.
Subtask 30-21-00-810-060-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) Make sure that electrical connector P17 of the W04 harness is correctly engaged in the receptacle of the NAI fan pressure-transducer.
(a) If it is not correctly engaged, engage it.
1 Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(b) If you find damage on the receptacle J17 of the NAI fan pressure-transducer:
1 Do a resistance check AWM 715134 between:
. Pin J17/3 and pin J17/12 of the NAI fan pressure-transducer
. Pin J17/4 and pin J17/11 of the NAI fan pressure-transducer
a If the resistance is more than 12.5 kohm:
Replace the [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
Do the test given in Para. 3.
5. Close-up(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) Make sure that electrical connector P17 of the W04 harness is correctly engaged in the receptacle of the NAI fan pressure-transducer.
(a) If it is not correctly engaged, engage it.
- Do the test given in Para. 3.
- Examine the electrical connector P17 of the W04 harness and the receptacle J17 of the NAI fan pressure-transducer for bent pins, contamination, corrosion or visual signs of damage.
1 Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(b) If you find damage on the receptacle J17 of the NAI fan pressure-transducer:
- Replace the PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 [4003DN] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
- Do the test given in Para. 3.
1 Do a resistance check AWM 715134 between:
. Pin J17/3 and pin J17/12 of the NAI fan pressure-transducer
. Pin J17/4 and pin J17/11 of the NAI fan pressure-transducer
a If the resistance is more than 12.5 kohm:
- Replace the PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 [4003DN] AMM 30-21-23-000-801 and AMM 30-21-23-400-801.
- Do the test given in Para. 3.
- Do a visual inspection on the electrical connector P13 of the WO4 harness for bent pins, contamination, corrosion or visual signs of damage.
* If you find damage on electrical connector P13: - Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
- Do the test given in Para. 3.
- Do a continuity check AWM 715134 of the W04 harness between:
. Pin P13/q of the EEC and pin P17/12 of the NAI fan pressure-transducer
. Pin P13/BB of the EEC and pin P17/4 of the NAI fan pressure-transducer
. Pin P13/p of the EEC and pin P17/3 of the NAI fan pressure-transducer
. Pin P13/T of the EEC and pin P17/11 of the NAI fan pressure-transducer.
- Replace the W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
- Do the test given in Para. 3.
Replace the
Do the test given in Para. 3.
Subtask 30-21-00-942-052-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.