DOC AIRBUS | TSM A320FTroubleshoot the Engine after a High (N1) Vibration event
TASK 71-00-00-810-856-A
Troubleshoot the Engine after a High (N1) Vibration event
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
3. Fault Confirmation
Subtask 71-00-00-710-118-A ** ON A/C NOT FOR ALL
Subtask 71-00-00-860-073-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:40:52 UTC
Troubleshoot the Engine after a High (N1) Vibration event
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 71-00-00-810-854-A | Troubleshoot the Engine after a Surge - Forward Thrust event |
| TSM TASK 77-31-00-810-802-A | PHMU CAN Fault |
| TSM TASK 77-32-00-810-824-A | D-Flange Monitoring Failure |
| TSM TASK 77-32-00-810-825-A | P-Flange Monitoring Failure |
| TSM TASK 79-35-00-810-808-A | Chip Detected Alert by ODM |
| AMM 71-00-00-700-802 | Test No. 8 - Vibration analysis (Vibration Survey) |
| AMM 71-00-00-710-807 | Function Test (Fan Trim Balance) |
| AMM 72-00-00-210-812 | General visual Inspection (GVI) of the Engine Exhaust Area |
| AMM 72-00-00-210-813 | General Visual Inspection (GVI) of the Engine Inlet Area |
| AMM 72-00-00-220-802 | Detailed Visual Inspection (DVI) of the Engine Mount Lugs (Engine Removed) |
| AMM 72-31-00-290-802 | Borescope Inspection of the Low Pressure Compressor (LPC) Assembly |
| AMM 72-53-00-200-801 | Borescope Inspection of the Low Pressure Turbine (LPT) Assembly |
| AMM 73-21-00-710-806 | Test No.7 - EEC Operation Test (Self Test) |
| AMM 79-00-00-281-802 | Inspection of the Magnetic Chip Collectors for Oil Contamination |
Subtask 71-00-00-710-118-A ** ON A/C NOT FOR ALL
A. Investigate the Engine after a High (N1) Vibration event
(1) Use this troubleshooting procedure to investigate the engine after a high (N1) vibration event. Excessive N1 vibration or N2 vibration is indicated on the flight deck as VIB N2 amber. The highest value between N1 vibration and N2 vibration will be reported as VIB N2. The maintenance messages related to high (N1) vibration will be set when high (N1) vibration is detected by the FADEC system.
(2) Use also this procedure to investigate the engine after a N1 vibration event higher than normal values but not over the amber limit.
(3) Look at the Table 1 for additional information how this fault is displayed on the flight deck.
Table 1 - Vibration: Flight Deck Indicated vs Actual
(4) Look to see if there is a report of high oil temperature that is set when the high N1 vibration occurred.
(a) If the oil temperature was high when high N1 vibration occurred, remove the engine from service.
(b) If the oil temperature was OK when high N1 vibration occurred, go to the next step.
(5) Using the Multipurpose Control and Display Unit (MCDU) test the FADEC system for any recorded faults AMM 73-21-00-710-806.
(6) Any EEC monitored faults are transmitted to the aircraft Centralized Fault Display Interface Unit (CFDIU). The MCDU allows interactive dialog with the EEC. Use the MCDU to review the previous flight leg fault information, scheduled maintenance fault information, ground fault information and divergence report. Look at the pilot log for a report of tactile vibration when the problem occurred. If there are any faults reported troubleshoot them first.
(7) Vibration characteristics are unique to each engine. A single reading is not very meaningful unless a sudden significant increase is encountered compared to engine initial installation levels.
4. Fault Isolation(1) Use this troubleshooting procedure to investigate the engine after a high (N1) vibration event. Excessive N1 vibration or N2 vibration is indicated on the flight deck as VIB N2 amber. The highest value between N1 vibration and N2 vibration will be reported as VIB N2. The maintenance messages related to high (N1) vibration will be set when high (N1) vibration is detected by the FADEC system.
(2) Use also this procedure to investigate the engine after a N1 vibration event higher than normal values but not over the amber limit.
(3) Look at the Table 1 for additional information how this fault is displayed on the flight deck.
Table 1 - Vibration: Flight Deck Indicated vs Actual
| Flight Deck Indication | Actual |
|---|---|
| VIB N1 | NF (Fan Vibration) |
| VIB N2 | N1 (LPC/LPT Vibration) or N2 (HPC/HPT Vibration). Determined by which input has the highest value. |
(a) If the oil temperature was high when high N1 vibration occurred, remove the engine from service.
(b) If the oil temperature was OK when high N1 vibration occurred, go to the next step.
(5) Using the Multipurpose Control and Display Unit (MCDU) test the FADEC system for any recorded faults AMM 73-21-00-710-806.
(6) Any EEC monitored faults are transmitted to the aircraft Centralized Fault Display Interface Unit (CFDIU). The MCDU allows interactive dialog with the EEC. Use the MCDU to review the previous flight leg fault information, scheduled maintenance fault information, ground fault information and divergence report. Look at the pilot log for a report of tactile vibration when the problem occurred. If there are any faults reported troubleshoot them first.
(7) Vibration characteristics are unique to each engine. A single reading is not very meaningful unless a sudden significant increase is encountered compared to engine initial installation levels.
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.
Subtask 71-00-00-810-126-A ** ON A/C NOT FOR ALL A. Do the steps that follow:
(1) If the crew alert warning messages related to the engine stall appear, refer to troubleshoot the engine after a surge - forward thrust event (Ref. TSM TASK 71-00-00-810-854).
(2) If the maintenance messages related to the oil debris overlimit detected by Oil Debris Monitoring (ODM) appear with the ECAM warning for oil chip detected, refer to chip detected alert by ODM (Ref. TSM TASK 79-35-00-810-808).
(3) If the maintenance messages related to the forward flange vibration sensor appear with amber crosses on the vibration display, refer to D-Flange monitoring failure (Ref. TSM TASK 77-32-00-810-824).
(4) If the maintenance messages related to the aft flange vibration sensor appear with amber crosses on the vibration display, refer to P-Flange monitoring failure (Ref. TSM TASK 77-32-00-810-825).
(5) If the maintenance messages related to the Power Health Monitoring Unit (PHMU) CAN Bus failure appear with amber crosses on the vibration display, refer to PHMU CAN fault (Ref. TSM TASK 77-31-00-810-802).
(6) Visually inspect the engine inlet area AMM 72-00-00-210-813.
(7) If you find indications of Foreign Object Damage (FOD), visually inspect the Low Pressure Compressor (LPC) (2.5) bleed discharge area for evidence of metallic debris.
(a) If you find metallic debris, remove the engine for service.
(8) If you find indications of FOD at the engine inlet and there is no evidence of metallic debris at the LPC (2.5) bleed discharge area, do a Borescope Inspection (BSI) of the LPC AMM 72-31-00-290-802.
(9) If you do not find any problems, visually inspect the engine exhaust aera AMM 72-00-00-210-812.
(a) If you find metallic debris, remove the engine from service.
(10) If you do not find any problems, inspect the Low Pressure Turbine (LPT) AMM 72-53-00-200-801.
(11) If you do not find any problems, inspect to make sure that the engine external hardware is secure including the engine-mounts and the engine vibration monitoring hardware AMM 72-00-00-220-802.
(12) If you do not find any problems, visually inspect the magnetic chip collectors for oil system contamination AMM 79-00-00-281-802.
(a) If there are indications of metal particles, remove the engine from service.
(13) If you do not find any problems, do a vibration survey AMM 71-00-00-700-802.
(a) As an option you can do a trim balance of the LPT at the same time as you do the vibration survey AMM 71-00-00-710-807.
(b) If the problem continues, remove the engine from service.
5. Close-up(1) If the crew alert warning messages related to the engine stall appear, refer to troubleshoot the engine after a surge - forward thrust event (Ref. TSM TASK 71-00-00-810-854).
(2) If the maintenance messages related to the oil debris overlimit detected by Oil Debris Monitoring (ODM) appear with the ECAM warning for oil chip detected, refer to chip detected alert by ODM (Ref. TSM TASK 79-35-00-810-808).
(3) If the maintenance messages related to the forward flange vibration sensor appear with amber crosses on the vibration display, refer to D-Flange monitoring failure (Ref. TSM TASK 77-32-00-810-824).
(4) If the maintenance messages related to the aft flange vibration sensor appear with amber crosses on the vibration display, refer to P-Flange monitoring failure (Ref. TSM TASK 77-32-00-810-825).
(5) If the maintenance messages related to the Power Health Monitoring Unit (PHMU) CAN Bus failure appear with amber crosses on the vibration display, refer to PHMU CAN fault (Ref. TSM TASK 77-31-00-810-802).
(6) Visually inspect the engine inlet area AMM 72-00-00-210-813.
(7) If you find indications of Foreign Object Damage (FOD), visually inspect the Low Pressure Compressor (LPC) (2.5) bleed discharge area for evidence of metallic debris.
(a) If you find metallic debris, remove the engine for service.
(8) If you find indications of FOD at the engine inlet and there is no evidence of metallic debris at the LPC (2.5) bleed discharge area, do a Borescope Inspection (BSI) of the LPC AMM 72-31-00-290-802.
(9) If you do not find any problems, visually inspect the engine exhaust aera AMM 72-00-00-210-812.
(a) If you find metallic debris, remove the engine from service.
(10) If you do not find any problems, inspect the Low Pressure Turbine (LPT) AMM 72-53-00-200-801.
(11) If you do not find any problems, inspect to make sure that the engine external hardware is secure including the engine-mounts and the engine vibration monitoring hardware AMM 72-00-00-220-802.
(12) If you do not find any problems, visually inspect the magnetic chip collectors for oil system contamination AMM 79-00-00-281-802.
(a) If there are indications of metal particles, remove the engine from service.
(13) If you do not find any problems, do a vibration survey AMM 71-00-00-700-802.
(a) As an option you can do a trim balance of the LPT at the same time as you do the vibration survey AMM 71-00-00-710-807.
(b) If the problem continues, remove the engine from service.
Subtask 71-00-00-860-073-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.
(1) Make sure that the work area is clean and clear of tools and other items.