Accident Overview
On September 12, 2020, about 2152 mountain daylight time, a Cessna 172H airplane, registration N3720R, was substantially damaged when it collided with terrain near Seeley Lake, Montana. The pilot and one passenger sustained fatal injuries, and one passenger was seriously injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Flight History
The airplane was based at Seeley Lake Airport (23S) and operated by a flying club. Earlier that day, the pilot flew from 23S to Bowman Field Airport (3U3) in Anaconda, Montana, for a golf event. The accident occurred during the return approach to 23S. A witness at 23S heard the aircraft approach from the south, pass the airport, and continue north until the sound faded. Another witness near the crash site reported that the engine “sputtered” before impact. The surviving passenger had no recollection of the event.
Local law enforcement initiated a search after hearing reports of a crash and located the wreckage early on September 13, about three-quarters of a mile north of 23S.
Pilot and Aircraft Information
The pilot held a private pilot certificate with a single-engine land rating but was not instrument rated. He was issued a third-class medical certificate on September 11, 2020, with the limitation requiring corrective lenses. At that time, he reported 550 total flight hours.
According to the flying club, the aircraft was to be returned with at least half fuel because 23S lacked fuel services. The club’s tach time log showed the pilot refueled with about 24 gallons at Deer Lodge City-County Airport (38S) on the day of the accident. It is unknown whether this stop occurred during the inbound or outbound leg of the flight.
Meteorological Conditions
A weather model indicated surface winds from the west at 4 knots, with a radiation inversion at 130 feet above ground level (agl) and a subsidence inversion at 558 ft agl. Smoke from wildfires in the Pacific Northwest was prevalent, with increased concentrated smoke levels from the surface to 1,000 ft agl near the accident site. No pilot reports (PIREPs) were filed within 75 miles around the accident time. AIRMET Sierra was in effect, warning of instrument flight rules (IFR) conditions and mountain obscuration due to haze and smoke. The pilot did not request a weather briefing from Leidos or ForeFlight, and no record of him obtaining weather information was found.
Sunset was at 1948, with the end of twilight at 2019. The moon was below the horizon at the time of the accident.
Wreckage and Impact Analysis
The accident site was in heavily wooded terrain at an elevation of about 4,325 ft, approximately 69 ft higher than the airport. The initial impact point was the top of 75-ft-tall trees, with the aircraft traveling about 365 ft through the treetops before coming to rest on a heading of about 152°. No post-impact fire occurred. The left wing separated and was found 159 ft from the main wreckage. The tachometer read 2,267.75 hours. Propeller blades showed chordwise scoring and leading edge gouges, with one blade having an aft twist and the other bent and twisted near the tip. The spinner dome was crushed with torsional deformation. The fuel selector was on both tanks, and residual fuel was found in the fuel strainer and electric fuel pump.
Postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. The propeller manufacturer noted that the damage was consistent with the propeller rotating under power at impact.
Medical and Pathological Information
An autopsy performed by the Montana Forensic Science Division determined the pilot’s cause of death as blunt force injuries. Toxicology tests detected no drugs of abuse.