# SDR ASAA2016083117877

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 31, 2016
- Submitted: September 6, 2016
- Operation: Air carrier
- Aircraft: [N492AS](https://openairdocs.org/aircraft/N492AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 44110
- Aircraft time: 2,937 hours, 1,005 cycles
- System (JASC): [4990 · APU Oil System](https://openairdocs.org/jasc/4990)
- Part: Bypass Switch
- Part number: 3043002
- Condition: Failed
- Location: Apu
- Stage of operation: TX
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2016083117877

## Discrepancy

AFTER STARTING APU ON TAXI IN, APU FAULT LIGHT ILLUMINATED AND AUTO SHUTDOWN OCCURRED.  RAN QRH,TURNED OFF APU SWITCH.  ACFT GROUNDED.  
ACCOMPLISHED FIM TASK 49-90, TASK 809.  PERFORMED MAGNETIC DRAIN PLUG INSPECTION REF AMM TASK 49-91-81.  NO METAL PARTICLES FOUND.  REPLACED OIL FILTER ELEMENTS REF AMM 49-91-12.  FILTERS CLEAN.  RAN APU FOR 15 MINUTES.  FAULT REOCCURRED.  CHECKED AND REPLACED THE FILTER BYPASS SWITCH FOR THE STARTER GENERATOR REF AMM 49-91-13.  OPERATED APU FOR 20 MINUTES.  FAULT CORRECTED.  NO LEAKS FOUND ON ANY COMPONENTS.  THIS CLEARS MEL 49-1B.

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