# SDR USA2002F00067

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 2, 2002
- Operation: Air carrier
- Aircraft: N434US
- Make and model: Boeing 737-4B7
- Registry model: [Boeing 737-4B7](https://openairdocs.org/model/boeing-737-4b7) (OpenAirDocs)
- Aircraft serial: 24556
- System (JASC): [4960 · APU Controls](https://openairdocs.org/jasc/4960)
- Part: Switch
- Part number: 38762594
- Condition: Faulty
- Location: Up Ceiling Fdr
- Stage of operation: CR
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USA2002F00067

## Discrepancy

ENROUTE, THE APU EXPERIENCED AN OVERSPEED CONDITION RESULTING IN AN AUTO SHUTDOWN OF THE APU.  THE NR 1 ENGINE GENERATOR/CSD WAS ALREADY ON MEL (DUE TO LEAKING), SO THE FLIGHT DIVERTED.  FLIGHT LANDED WITHOUT FURTHER INCIDENT.  NO EMERGENCY WAS DECLARED.  MAINTENANCE REMOVED AND REPLACED THE APU ELECTRONIC 3 SPEED SWITCH.  OPERATIONAL CHECK GOOD.  ACCOMPLISHED SUCCESSFUL INFLIGHT START OF APU.  CLEARED AND REMOVED MEL ON NR 1 ENGINE GENERATOR/ CSD BY REPLACING THE NR 1 ENGINE CSD (PN 735511A).  OPERATIONAL CHECK AND LEAK CHECK GOOD.

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