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
