Engine Pistons

The following information is derived from the FAA's Service Difficulty Reports and Aviation Maintenance Alerts


Beech C33 Debonair

Broken Rings And Skirts

The oil quick-drain valve would not lock open. Inspection revealed metal in the sump. The oil filter was removed and cut open; no visible contamination was noted. An oil sample and compression tests came back normal. Teardown revealed three piston skirts were broken, and piston ring pieces were in the sump. The engine was removed from service.

Part total time: 1099.0 hours

Cessna 152

Piston Crown Failure

Shortly after takeoff, the engine began to run rough. Following an uneventful landing at the departure airport, inspection revealed oil leaking from breather tube and the #1 cylinder had no compression. Part of the piston’s top was missing.

Part total time: 721.0 hours

Cessna 182A

Broken Piston

On approach, the pilot noticed considerable vibration and mechanical knocking noise. Serious metal contamination was found on the oil screen. Engine teardown revealed  the #3 piston in multiple pieces and the #3 connecting rod was bent.

Part total time: 350.0 hours

Cessna 310Q

Broken Piston Skirt

Cylinder was removed due to a crack. The #4 piston skirt was found broken off at the 4th ring landing. Engine was removed. This particular airplane has experienced broken piston skirts in three different engines.

Part total time: 328.0 hours

Cessna 402C Businessliner

Preignition Failure

Right engine manifold pressure dropped in climb; engine ran rough, then failed. Aircraft landed safely. Inspection revealed a preignition event in the #5 cylinder caused the piston to break apart, with significant metal contamination throughout. Spark plug insulator failure is suspected. The engine was replaced.

Part total time: 2115.0 hours

Cessna 421B Golden Eagle

Cracked Piston-Pin Bosses

Oil filter inspection noted large aluminum chips. Investigation revealed the #2 piston was severely cracked through both piston-pin bosses.

Part total time: 644.0 hours

Lancair IV-P Experimental

Broken Skirts And Rings

During a routine inspection, a crack was found in the #6 cylinder’s intake area. Cylinder removal revealed a large part of the piston skirt was missing, plus a broken oil control ring and cracks near the piston-pin area. Metal was found in the oil filter. Cause unknown.

Part total time: 550.0 hours



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