# SDR UIEA2020040600708

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 2, 2020
- Submitted: April 6, 2020
- Operation: Air carrier
- Aircraft: [N416MC](https://openairdocs.org/aircraft/N416MC), registered now
- Make and model: Boeing 747-47UF
- Registry model: [Boeing 747-47UF](https://openairdocs.org/model/boeing-747-47uf) (OpenAirDocs)
- Aircraft serial: 32838
- Aircraft time: 75,888 hours, 12,564 cycles
- System (JASC): [4960 · APU Controls](https://openairdocs.org/jasc/4960)
- Part: Sensor
- Part number: 391140401B
- Part serial: EM19792
- Condition: Faulty
- Location: Apu
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2020040600708

## Discrepancy

N416MC REQUESTED TO RETURN TO AMS TO TROUBLESHOOT DEFERRED APU BECAUSE OF SCHEDULE AND GROUND SUPPORT EQUIPMENT AVAILABLE AT RIX, OAI. FLIGHT OPERATION REQUEST.(<P>TROUBLESHOOTING CARRIED OUT PER FIM FOR CMC FAULT 49091. CHECKED INLET PLENUM FOR OBSTRUCTIONS FOUND. CHECKED CHIP DETECTORS. FOUND SATISFACTORY. REPLACED N1 SPEED SENSOR IAW AMM 49-61-02. REPLACED DIVERTER VALVE IAW AMM 49-52-04 (OFF PART: PN 3900430, SN F55969), REPLACED APU FUEL FILTER IAW AMM 49-31-00 (OFF PART: PN ACB881F25, NSN). APU OPS CHECK SATISFACTORY IAW AMM 49-11-00.</P>)

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