Accident Details
Probable Cause and Findings
Incorrect connecting rod installation, which resulted in the failure of the nos. 5 and 6 connecting rods and subsequent total loss of engine power.
Aircraft Information
Registered Owner (Current)
Analysis
On December 2, 2020, about 2115 central standard time, a Bellanca 17-30A, N28067, was substantially damaged when it was involved in an accident near Arden Hills, Minnesota. The pilot and passenger and an occupant of the motor vehicle were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot stated the accident flight was a night sightseeing flight around the city. About 10 minutes after takeoff, he heard a loud “bang,” and the engine began to vibrate. Shortly thereafter, the engine lost power completely. The pilot made a gear-down forced landing on an interstate highway. During the landing roll, the airplane struck a vehicle and highway divider.
Postaccident examination revealed both wings were bent. In addition, a hole was observed on the top of the engine crankcase, and the cylinder Nos. 5 and 6 connecting rods were missing.
An engine examination revealed a large amount of metal debris in the oil pan. The oil filter also contained metal chips and filings. Recovered fragments included portions of the two connecting rods, the corresponding rod caps, and the associated rod bolts and nuts. Two rod cap nuts were found loose in the oil pan without any portion of the associated rod cap bolts. In addition, one rod bolt retained by the connecting rod was recovered but did not have a nut on the threaded end. The other rod bolts exhibited mechanical damage, separated threaded portions, or were not located.
Airplane maintenance records indicated that the engine had accumulated 1,296 hours since overhaul which was completed about 16 years prior to the accident. A maintenance entry dated September 13, 2012, indicated that the Nos. 1, 4 and 6 cylinders were removed and reinstalled due to low compression. It is not known if the connecting rods were removed at this time. According to the most recent annual inspection, completed on October 7, 2020, the engine had accumulated 396 hours since the removal and replacement of cylinder Nos. 1, 4, and 6. The No. 6 cylinder was replaced about 8 years and 396 hours time-in-service prior to the accident.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# CEN21LA073