# SDR ASAA2021012633954

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 26, 2021
- Submitted: January 29, 2021
- Operation: Air carrier
- Aircraft: [N508AS](https://openairdocs.org/aircraft/N508AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35691
- Aircraft time: 45,629 hours, 13,526 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Fault Message
- Condition: Unknown
- Location: Apu Bay
- Stage of operation: CR
- How discovered: V
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021012633954

## Discrepancy

FAULT LIGHT ILLUMINATED DURING APU START TWICE AT FL360.  SUCCESSFUL CSS ACCOMPLISHED AFTER FAULT LIGHT EXTINGUISHED AT FL310.  GROUNDED-YES.  PERFORMED B737-800 FIM 49-30 TASK 803, OVERTEMP SHUTDOWN, APU BITE TEST FAULT HISTORY MAINT MESSAGE, CDU SHOWS 49-31016.  VISUAL INSPECTION GOOD ON TAIL CONE AREA & ADJACENT CONTROL SURFACES AT THIS TIME.  INSPECTED ON GROUND ONLY.  PERFORMED APU STARTING AND OPERATION, REF B737-800 AMM 49-11-00-860-801 APU STARTED FINE WITH NO FAULT LIGHT ILLUMINATED.  PERFORMED APU BITE PROCEDURE, REF FIM 49-60 TASK 801, NO MAINT MESSAGE NOTED AT THIS TIME.

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