The private pilot reported that, as he approached the airport in the Beech V35, he noted “a sudden and severe noise and vibration” and “a…stream of gray smoke from under the right side of the engine cowling,” followed by a loss of engine power.
He made a forced landing near Katy, Texas, and the airplane sustained substantial damage to the fuselage and right wing.
Post-accident engine examination revealed two holes in the top of the crankcase near the Nos. 3 and 4 cylinders. A teardown examination of the engine revealed that the No. 4 connecting rod had failed due to oil starvation, which resulted in a catastrophic engine failure.
Foreign debris, which was similar to a paper towel, was recovered from the engine oil sump and the oil pickup screen. Most of the screen area was obstructed by the debris, which had interrupted the oil flow from the sump to the engine.
The airplane maintenance records noted that the alternator and alternator drive gear were replaced about eight weeks before the accident. The engine had been operated about 24 hours since the alternator replacement. The starter and starter adapter were replaced the day before the accident flight.
The engine had been operated about 15 minutes since the most recent maintenance work was performed. It is likely that maintenance personnel left the paper towel in the engine during the recent maintenance work, which resulted in oil starvation, the failure of the connecting rod, and the catastrophic engine failure and subsequent total loss of engine power.
Probable cause: Maintenance personnel’s failure to remove a paper towel from the engine during recent maintenance, which resulted in oil starvation, the failure of a connecting rod, and a catastrophic engine failure and subsequent total loss of engine power.
This July 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.