# SDR 2026FA0000342

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 9, 2026
- Submitted: May 9, 2026
- Operation: General aviation
- Engine: Lyc O320A2B
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Thrust Button
- Part number: SL12892
- Part serial: 250630000027855
- 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/2026FA0000342

## Discrepancy

INSPECTION PERFORMED SHORTLY AFTER MAJOR ENGINE OVERHAUL DUE TO SUSPECTED DEFECTIVE SUPERIOR ROCKER SHAFT THRUST BUTTONS INSTALLED AT MAJOR OVERHAUL. THRUST BUTTONS WERE PARTIALLY MELTED, DEFECTIVE THRUST BUTTONS 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 SUSPECT LOT NUMBER THRUST BUTTONS INSTALLED IN THEIR ENGINES TO INFORM THEM OF OUR FINDINGS AND TO REMOVE THE PARTS FROM SERVICE. SUSPECT LOT NUMBERS IN OUR INVENTORY WERE QUARANTINED.

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