# SDR ASAA2020040632586

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 31, 2020
- Submitted: April 6, 2020
- Operation: Air carrier
- Aircraft: [N529AS](https://openairdocs.org/aircraft/N529AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35198
- Aircraft time: 38,799 hours, 11,475 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Unknown
- Condition: Malfunctioned
- Location: Apu
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020040632586

## Discrepancy

APU FAILED START AT FL 380 TWO TIMES. FAULT LIGHT ILLUMINATED DUE TO OVERTEMP. SUCCESSFUL CSS ACCOMPLISHED AFTER FAULT LIGHT EXTINGUISHED. GROUNDED - YES. PERFORMED APU BITE TEST, CURRENT STATUS NO FAULTS. FOUND FAULT IN HISTORY FOR AN OVERTEMP SHUTDOWN MAINT MSG 49-3106. STARTED APU, OPS CK GOOD. CHECKED AND RELEASED PER MEL 49-99A. APU CSS CAPABILITY IS COMPROMISED. REF L.P. 12058907. CSS SUCCESSFUL. CLEARS MEL 49-99A.

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