# SDR ECPR20260731001

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 27, 2026
- Submitted: July 31, 2026
- Operation: General aviation
- Aircraft: [N555PU](https://openairdocs.org/aircraft/N555PU), registered now
- Make and model: Piper PA-28-161
- Registry model: [Piper PA-28-161](https://openairdocs.org/model/piper-pa-28-161) (OpenAirDocs)
- Aircraft serial: 2842092
- Aircraft time: 17,951 hours
- Engine: Lyc O320D3G
- Engine time: 5,668 hours
- Propeller: Snsnch 74DM
- System (JASC): [7421 · Spark Plug/Igniter](https://openairdocs.org/jasc/7421)
- Part: Spark Plug
- Part number: UREM38E
- Condition: Cracked
- Location: Zone 400
- Component: Cylinder, Lyc
- Component part number: LW12416
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ECPR20260731001

## Discrepancy

A SPARK PLUG WAS REPLACED DURING A SCHEDULED MAINTENANCE INSPECTION. DURING THE POST-MAINTENANCE OPERATIONAL CHECK, THE ENGINE SUDDENLY DEVELOPED ROUGHNESS AND A PARTIAL LOSS OF POWER. SUBSEQUENT INSPECTION FOUND THE SPARK PLUG HAD COMPLETELY SEPARATED INTO TWO PIECES AT A POINT BETWEEN THE SPARK PLUG GASKET BOSS AND THE HEXAGONAL NUT PORTION (WHAT TEMPEST REFERS TO AS THE HOT LOCK ASSEMBLY). THIS CAUSED A LOSS OF COMPRESSION ON THAT CYLINDER AND IGNITION FAILURE OF THAT SPARK PLUG. A PRECAUTIONARY CHECK OF SPARK PLUGS IN HELD IN STOCK DISCOVERED FOUR SPARK PLUGS WITH CRACKING IN THIS AREA (STILL SEALED IN SEALED FACTORY PLASTIC SLEEVES. THE SPARK PLUGS WERE FROM LOT # 1VGM.

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