# SDR 2026FA0000343

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 9, 2026
- Submitted: May 9, 2026
- Operation: General aviation
- Engine: Lyc O360A1P
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Thrust Button
- Part number: SL12892
- Part serial: 250923000028574
- Condition: Melted
- Location: Cylinders
- 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/2026FA0000343

## Discrepancy

INSPECTION PERFORMED SHORTLY AFTER MAJOR ENGINE OVERHAUL DUE TO SUSPECTED DEFECTIVE SUPERIOR ROCKER SHAFT THRUST BUTTONS INSTALLED AT MAJOR OVERHAUL. ALL THRUST BUTTONS WERE PARTIALLY MELTED AND DEFORMED WITH MELTED PLASTIC DEBRIS FOUND IN ROCKER COVER. DEFECTIVE THRUST BUTTONS WERE REMOVED AND REPLACED WITH LYCOMING THRUST BUTTONS P/N LW-12892. INFORMATION THAT WE RECEIVED STATED THAT FAULTY THRUST BUTTONS WILL FLOAT IN WATER AND GOOD PARTS WILL SINK. WE PERFORMED THIS TEST ON EVERY LOT NUMBER IN OUR INVENTORY AND FOUND SEVERAL LOT NUMBER BATCHES THAT FLOAT. WE THEN CONTACTED ANY CUSTOMERS WITH THE DEFECTIVE LOT NUMBER THRUST BUTTONS INSTALLED IN THEIR ENGINES TO INFORM THEM OF OUR FINDINGS AND TO REMOVE THE PARTS FROM SERVICE. DEFECTIVE LOT NUMBERS IN OUR INVENTORY WERE QUARANTINED.

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