# SDR NACA20040058

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 9, 2004
- Submitted: November 10, 2004
- Operation: Air carrier
- Aircraft: N6174C
- Make and model: Doug DC-6A
- Registry model: [Doug DC-6A](https://openairdocs.org/model/douglas-dc-6a) (OpenAirDocs)
- Aircraft serial: 44075
- Aircraft time: 51,014 hours
- Engine: Pwa R2800CB3
- Engine time: 658 hours
- System (JASC): [7421 · Spark Plug/Igniter](https://openairdocs.org/jasc/7421)
- Part: Spark Plug
- Part number: URHB32E
- Condition: Cracked
- Location: Nr 12 Cylinder
- Part time: 18 hours
- Stage of operation: CR
- How discovered: O
- Nature of condition: R, J
- Precautionary procedure: E, A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/NACA20040058

## Discrepancy

NR 1 ENGINE SHUT DOWN DUE TO BACKFIRING AND RUNNING ROUGH.  FOUND NR 12 CYLINDER FRONT AND REAR SPARK PLUGS WITH CRACKED CERAMICS.  REPLACED PLUGS, OP CHECKED GOOD.

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