DOC AIRBUS | TSM A320FFailure of the N1 Sensor on Engine 1
1. Possible Causes
· wiring
· EEC ( 4000KS )
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. AMM 24-41-00-861-002 Energize the Aircraft Electrical Circuits from the External Power
Ref. AMM 24-41-00-862-002 De-energize the Aircraft Electrical Circuits Supplied from the External
Power
Ref. AMM 31-60-00-860-002 EIS Stop Procedure
Ref. AMM 70-23-15-912-010 Connection of Electrical Connectors
Ref. AMM 71-00-00-710-018 Discontinued Start, Restart and Shutdown Procedures
Ref. AMM 71-00-00-710-043 Normal Engine Automatic Start Procedure
Ref. AMM 71-00-00-710-047 Normal Engine Manual Start Procedure
Ref. AMM 71-13-00-410-010 Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 73-22-34-000-010 Removal of the Electronic Engine Control (EEC)
Ref. AMM 73-22-34-400-010 Installation of the Electronic Engine Control (EEC)
Ref. ASM 73-25-13
Ref. AMM 77-11-00-860-010 Change over the N1 Rotational Speed Indicating Probe Harness Leads
400VS-1, 400VS-2, 400VS-5 and 400VS-6
Ref. AMM 78-32-00-410-010 Closing of the Thrust Reverser Halves
N1 Sensor SHEET 1
Figure 77(IAE)-00-00-991-00100-A / SHEET 1/1 - N1 Sensor not printed, as per printing preferences
3. Fault Confirmation
Subtask 77-00-00-860-050-A
A. Job Set-up
(1) Energize the aircraft electrical circuits
Ref. AMM 24-41-00-861-002 .
(2) On the panel 50VU, release the ENG FADEC GND PWR 1 pushbutton switch.
Subtask 77-00-00-710-050-A
B. Test
(1) On the panel 50VU, push the ENG FADEC GND PWR 1 pushbutton switch and release it again.
NOTE: This action resets the FADEC memory.
(2) Adjust the brightness of the MCDU screen.
(3) Push the INIT mode key. The INIT page comes into view.
(4) Enter a new flight number.
(5) Start the engine 1 by the normal engine automatic start procedure Ref. AMM 71-00-00-710-043 or
the normal engine manual start procedure Ref. AMM 71-00-00-710-047 .
NOTE: Operation of the engine for at least 3 minutes erases the LAST LEG REPORT related to the
last flight and the new fault is recorded in the EEC LAST LEG REPORT.
(6) Do a shutdown of the engine 1 by the discontinued start, restart and shutdown procedure Ref.
AMM 71-00-00-710-018 .
(7) Read the LAST LEG REPORT and the scheduled maintenance report of the FADEC (1A and 1B)
menu on the MCDU (Ref. 70-00-00 Page Block 301 Task Supporting Data).
(a) Make a record of the maintenance message.
(b) Make a record of the channel FADEC 1A or FADEC 1B which found the fault.
(8) Fully decrease the brightness of the MCDU screen (display off).
4. Fault Isolation
(Ref. Fig. N1 Sensor SHEET 1)
Subtask 77-00-00-810-050-A
A. If the test gives the maintenance message N1 SENS/HC/EEC1:
· Change over the N1 rotational speed indicating probe harness leads Ref. AMM 77-11-00-860-010 .
NOTE: Channel which shows faults should be moved to the spare pick-up and at the next engine shop
visit the N1 speed probe must be replaced.
(1) If a channel has already been moved to the spare pick-up and the N1 speed probe has been
identified as the cause through troubleshooting within this procedure then the engine must be
removed for N1 speed probe replacement.
(2) If the test confirms the fault:
· Read the fault code shown on the FLIGHT DATA and GROUND DATA of the FADEC (1A and 1B)
menu on the MCDU (Ref. 70-00-00 Page Block 301 Task Supporting Data).
· Make a record of the fault code.
(a) If the FADEC 1A menu gives the fault code N1L:
· Disconnect the electrical harness connector (4000KS-J2) from the EEC (4000KS)
· At the electrical connector (4000KS-J2), do a check of the resistance between:
. pins L and d (35 to 100 ohms).
1 If the resistance between the pins L and d is not between 35 and 100 ohms:
· Do a check and repair the wiring from the terminal block (4000VS) to the EEC (4000KS):
pins 1, 2 to pins J2/L, d Ref. ASM 73-25-13.
2 Connect the electrical connector (4000KS-J2) to the EEC (4000KS) Ref.
AMM 70-23-15-912-010 .
(b) If the FADEC 1B menu gives the fault code N1L:
· Disconnect the electrical harness connector (4000KS-J8) from the EEC (4000KS)
· At the electrical connector (4000KS-J8), do a check of the resistance between:
. pins L and d (35 to 100 ohms).
1 If the resistance between the pins L and d is not between 35 and 100 ohms:
· Do a check and repair the wiring from the terminal block (4000VS) to the EEC (4000KS):
pins 3, 4 to pins J8/L, d Ref. ASM 73-25-13.
2 Connect the electrical connector (4000KS-J8) to the EEC (4000KS) Ref.
AMM 70-23-15-912-010 .
(c) If the FADEC 1A and 1B menus give the fault code N1XCF:
· Disconnect the electrical harness connector (4000KS-J2) from the EEC (4000KS)
· At the electrical connector (4000KS-J2), do a check of the resistance between:
. pins L and d (35 to 100 ohms).
1 If the resistance between the pins L and d is not between 35 and 100 ohms:
· Do a check and repair the wiring from the terminal block (4000VS) to the EEC (4000KS):
pins 1, 2 to pins J2/L, d Ref. ASM 73-25-13.
2 Connect the electrical connector (4000KS-J2) to the EEC (4000KS) Ref.
AMM 70-23-15-912-010 .
3 If the resistance values are in the specified limits:
· Disconnect the electrical harness connector (4000KS-J8) from the EEC (4000KS)
· At the electrical connector (4000KS-J8), do a check of the resistance between:
. pins L and d (35 to 100 ohms).
a If the resistance between the pins L and d is not between 35 and 100 ohms:
· Do a check and repair the wiring from the terminal block (4000VS) to the EEC
(4000KS): pins 3, 4 to pins J8/L, d Ref. ASM 73-25-13.
4 Connect the electrical connector (4000KS-J8) to the EEC (4000KS) Ref.
AMM 70-23-15-912-010 .
(3) If the fault continues:
· Replace the EEC ( 4000KS ) Ref. AMM 73-22-34-000-010 and Ref. AMM 73-22-34-400-010 .
Subtask 77-00-00-710-051-A
B. Do the test given in Para. 3.
5. Close-up
Subtask 77-00-00-860-051-A
A. Put the aircraft back to its initial configuration.
(1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
Ref. AMM 31-60-00-860-002 .
(2) On the panel 50VU, push the ENG FADEC GND PWR 1 pushbutton switch.
(3) De-energize the aircraft electrical circuits
Ref. AMM 24-41-00-862-002 .
(4) Make sure that the thrust reverser halves 451AL and 452AR are closed Ref.
AMM 78-32-00-410-010 .
(5) Make sure that the fan cowls 437AL and 438AR are closed Ref. AMM 71-13-00-410-010 . [Rev.6 from Feb 2017] 2026.04.04 04:37:47 UTC