Accident Overview
On September 2, 2018, at approximately 0920 eastern daylight time, a Stinson 108, registration N4059C, was substantially damaged during a forced landing near Indiana County Airport (IDI) in Indiana, Pennsylvania. The student pilot incurred serious injuries, and the flight instructor sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight, which originated around 0800. The flight was conducted under 14 Code of Federal Regulations Part 91.
Flight Sequence
According to the flight instructor, the student pilot performed a preflight inspection, including fuel sampling, with no anomalies noted. Approximately 12.5 gallons of fuel were present in each tank, totaling 25 gallons. The flight departed using the right fuel tank initially, switching to the left tank after about 35 minutes of air work outside the traffic pattern. They returned to the pattern and performed about five landings, using full carburetor heat during each approach. During the initial climb of the last takeoff, engine response was normal until about 300 ft above ground level, at which point the engine abruptly lost total power. The flight instructor took control, pitched for airspeed, and attempted to regain power. He turned toward a clearing, but the airplane struck trees before impacting the ground.
Aircraft Damage and Engine Examination
The airplane came to rest upright in high brush, with substantial damage to the forward fuselage. An FAA inspector examined the engine: the engine mount was fractured in three places, but no holes were found in the crankcase. Crankshaft continuity was confirmed from the propeller hub to the accessory section, and magnetos produced spark on all towers. Fuel samples from the wings contained solid debris, similar to dirt and orange sealant. Fuel from the gascolator also contained debris. The carburetor was removed and disassembled; an air filter element was lodged in the throat of the carburetor venturi, and debris was found in the fuel inside the carburetor bowl and in the carburetor fuel inlet screen.
Maintenance History
The owner had possessed the airplane for about two and a half years, during which it flew about 20 hours. Between August 2016 and August 2018, the engine received all new cylinders and the wings were recovered. The most recent annual inspection was completed on May 24, 2018, at a total time of 2493.8 hours. At the time of the accident, the airplane had accumulated 2498 total hours.
Additional Information
In a conversation with the student pilot, he stated that no fuel contamination was noted from the airport's fuel storage tanks around the time of the accident.