Accident Overview
On July 12, 2023, at approximately 1624 Alaska daylight time, a Stinson 108 airplane, registration N97719, sustained substantial damage during a forced landing near Ninilchik, Alaska. The pilot, who was the sole occupant, was not injured. The airplane was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Sequence of Events
The pilot reported departing Homer Airport (HOM) with a destination of Anchorage, Alaska. A few miles northwest of Ninilchik Airport (NIN), he noticed a loss of engine power accompanied by decreasing oil pressure. Assessing that he was too far from NIN to return, the pilot elected to perform a forced landing onto a road. During the landing roll, the right wingtip struck a traffic sign, resulting in substantial damage to the right wing.
Postaccident Examination
Examination of the engine after the accident revealed that the No. 1 cylinder had fractured from the engine and remained partially attached only by the exhaust tubes and intake manifold. The intake valve head and stem were fractured approximately one inch from the interior base of the valve. The piston and intake valve were destroyed by internal forces within the engine, and their fragments were not located.
Aircraft and Maintenance History
The pilot reported that the engine had accumulated a total time of 626 hours at the time of the accident. The last annual inspection was completed 12 months prior to the accident, at which point the engine had a total time of 556.4 hours. According to the engine logbook, the manufacturer's recommended time between overhauls is 1,200 hours.