Service difficulty report · Thrust Button

Difficulty date
May 9, 2026
Submitted
May 9, 2026
Operation
General aviation
Engine
Lyc O320A2B
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

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

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.