# SDR ASAA2020121033681

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 10, 2020
- Submitted: December 15, 2020
- Operation: Air carrier
- Aircraft: [N588AS](https://openairdocs.org/aircraft/N588AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35685
- Aircraft time: 47,168 hours, 14,080 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Exciter
- Part number: 38880587
- Part serial: 130782
- Condition: Faulty
- Location: Apu
- Part time: 5,038 hours, 8,683 cycles
- Stage of operation: IN
- How discovered: 9
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020121033681

## Discrepancy

WHILE ACCOMPLISHING APU DEPRESERVATION APU WOULD NOT START.  GROUNDED-YES.  APU BITE SHOWED MESSAGE 49-41011, NO FLAME SHUTDOWN.  INITIATED B737-800 FIM 49-40 TASK 802.  IGNITER NOT AUDIBLE.  REPLACED IGNITER AND IGNITER LEADS, REF B737-800 AMM 4-41-51 AND 49-41-52.  NO HELP FAULT REMAINS.  REMOVED AND REPLACED APU IGNITION UNIT, PER AMM 49-41-31.  OPERATIONS TEST GOOD, NO FAULTS NOTED.

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