# SDR 95ZZZX6381

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 17, 1995
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: N3380Q
- Make and model: Cessna 421B
- Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (OpenAirDocs)
- Aircraft serial: 421B0264
- Engine: Cont GTSIO520H
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Piston
- Part number: 632585
- Condition: Wrong Part
- Location: Lt/Rt Engine
- Stage of operation: IN
- Nature of condition: W
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/95ZZZX6381

## Discrepancy

FOUND 11 OUT OF 12 CYLINDERS WITH THIS P/N PISTON WHICH IS NOT APPROVED FOR USE IN GTSIO520 ENGINES.  PISTONS WERE SENT FROM ECI AS PART OF A GTSIO-520 CYLINDER ASSY.  P/N 632585 CYLINDER IS DOMED WITH NO STEEL INSERT FOR THE TOP RING GROOVE.  THE CORRECT PISTON FOR THE GTSIO520 ENGINE IS FLAT WITH A STEEL INSERT.  ONE PISTON WAS CORRECT ON LT ENGINE, BUT THIS WOULD CAUSE AN OUT OF BALANCE CONDITION.

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