04/08/21
Message Overview:
Message Description:
Auxiliary Power Unit (APU) protective shutdown - engine failed to reach 99% speed within 30 seconds of starter cutout.
Possible Causes:
- Engine Combustor
- Engine
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Fault Confirmation Procedure:
- Message# = 7
- {Term Definitions}
- APU-43 XX 352 01 EXCT XXXX-XXTX XXXX-XXXX XXXX-XXXX 352: 26; APU S/D SLOWSTRT COND2
Quick Links:
| Removal of the Battery | AMM 24-32-01-000-801 |
| Installation of the Battery | AMM 24-32-01-400-801 |
| Removal of the Fuel Control Unit | AMM 49-31-01-000-801 |
| Installation of the Fuel Control Unit | AMM 49-31-01-400-801 |
| Removal of the Fuel Solenoid Valve | AMM 49-31-09-000-801 |
| Installation of the Fuel Solenoid Valve | AMM 49-31-09-400-801 |
| Removal of the Ignition Unit | AMM 49-41-01-000-801 |
| Installation of the Ignition Unit | AMM 49-41-01-400-801 |
| Removal of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) | AMM 49-61-01-000-801 |
| Installation of the Auxiliary Power Unit (APU) Electronic Control Unit (ECU) | AMM 49-61-01-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- This condition could be due to restricted fuel flow, engine flame out of the combustor, or mechanical engine failure.