# SDR ASAA2019041989052

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 18, 2019
- Submitted: April 20, 2019
- Operation: Air carrier
- Aircraft: [N581AS](https://openairdocs.org/aircraft/N581AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35188
- Aircraft time: 45,451 hours, 13,577 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Exciter
- Part number: 38880585
- Part serial: 000218016675
- Condition: Failed
- Location: Apu
- Part time: 10,146 hours, 19,430 cycles
- Stage of operation: IN
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2019041989052

## Discrepancy

WHILE TOWING A/C APU FAULT LIGHT CAME ON AND APU UNABLE TO START. GROUNDED - YES. PERFORMED APU BITE FOUND FAULT 49-31175 WAS 75 STARTS OLD AND NOT LIKELY RELATED TO CURRENT PROBLEM. INSPECTED APU WIRE HARNESS AND RANG PINS ON FCU PER B737-800 FIM 49-32 TASK 805 WITH NO DEFECTS NOTED. STARTED APU MULTIPLE TIMES WITH NO FAULTS.

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