No fatalities

13 Jul 2023: AERONCA 7DC (N83391) — Ninilchik, AK

Ninilchik, AK, United States

On 13 Jul 2023, an AERONCA 7DC (registration N83391) was involved in an aviation accident near Ninilchik, AK. No fatalities were reported. Investigators recorded the probable cause as: A total loss of engine power due to a shift of a crankshaft main bearing, which resulted in a lack of lubrication and subsequent overheating and failure of the engine crankshaft. This summary draws on records from NTSB; 7 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

On July 12, 2023, an Aeronca 7DC (N83391) sustained substantial damage during a forced landing near Ninilchik, Alaska, following a loss of engine power. The pilot and passenger were uninjured. Postaccident examination revealed a spun main bearing blocking the oil port.

Accident Overview

On July 12, 2023, at approximately 1620 Alaska daylight time, an Aeronca 7DC airplane, registration N83391, was substantially damaged when it was involved in an accident near Ninilchik, Alaska. The pilot and passenger reported no injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.

Pilot Report

The pilot reported that he and a friend were on a scenic flight from Homer Airport (HOM) to Soldotna Airport (SXQ). En route, he noticed that the engine was not producing enough power for the set power setting. At full throttle, the engine was only achieving about 2,400 rpm. The pilot executed memory checklist items for loss of engine power, which included applying carburetor heat, but there was no change in engine performance. He also opened both wing tanks to increase fuel flow to the header tank, with no improvement. Subsequently, the oil pressure and oil temperature gauges both indicated zero. As the pilot initiated a climb to clear rising terrain, the engine began to vibrate violently and then lost all power.

He performed a forced landing onto a road. After touchdown, he veered left to avoid cars, and the airplane struck a guardrail before nosing over. The accident resulted in substantial damage to the fuselage and wings.

Postaccident Examination

A postaccident examination of the engine revealed that the crankshaft's No. 1 main bearing had spun, smearing metal into the crankcase and blocking the oil port. Numerous fragments of bearing material were found inside the case. The owner was unable to provide maintenance records for the engine.

Contributing factors

Damaged/degraded