History of Flight
On December 16, 2014, about 1620 mountain standard time, a Piper PA-18-150 Super Cub, registration N5989Z, impacted a hill while maneuvering near Ronan, Montana. The commercial pilot was fatally injured, and the pilot-rated passenger sustained serious injuries; the airplane sustained substantial damage. The local personal flight was operated under 14 CFR Part 91 and departed Ronan Airport about 1600. Daytime visual meteorological conditions prevailed; no flight plan was filed.
The passenger, a student pilot, had purchased the airplane about six weeks prior. He had recently bought a new propeller, and the pilot—also an aviation mechanic—installed it just before the flight. After departure, they maneuvered locally with the pilot as pilot-in-command. As they approached hills, they checked airplane performance. The pilot saw a coyote and performed a wingover maneuver: the airplane banked left and the pilot pulled up. About 20 feet from terrain, the pilot said, "I don't think we are going to make it." The airplane collided with terrain. The passenger reported no pre-impact mechanical malfunctions.
Witnesses saw the airplane maneuvering at low altitude minutes before impact. One heard the engine accelerate just before impact; another observed erratic maneuvers resembling crop dusting, with rapid climbs and descents.
Personnel Information
The 33-year-old pilot held a commercial pilot certificate with single-engine land, single-engine sea, and instrument airplane ratings, plus an airframe and powerplant mechanic certificate. His most recent second-class medical was issued June 27, 2014, without limitations. Personal logbooks were not recovered; his last FAA medical application reported 3,000 total flight hours, with 120 hours in the previous six months.
The passenger held a student pilot certificate issued October 2014. His logbooks indicated about 40 hours total time, all in the accident airplane, with first solo about one month prior.
Aircraft Information
The Piper PA-18-150 Super Cub (serial number 18-8247) was manufactured in 1965 and equipped with a Lycoming O-320-A2B engine (serial number L-15095-27A). The passenger purchased the airplane in October 2014. The most recent annual inspection of airframe and engine was performed September 12, 2014. The pilot had installed a Brorer 82/42 propeller just before the accident.
Meteorological Information
A METAR from Missoula International Airport (about 40 miles south) about 30 minutes before the accident reported: wind from 280° at 4 knots, temperature -01°C, dew point -07°C, overcast ceiling at 6,000 ft, altimeter 29.98 inHg. According to the U.S. Naval Observatory, the sun was about 3° above the horizon on an azimuth of about 230°, with local sunset at 1647.
Wreckage and Impact Information
The wreckage was on a steep east-facing hillside, about 100 feet below the peak on a 45° slope. The accident site was about 5 nautical miles from Ronan Airport on a bearing of about 295°. The debris field was oriented on a heading of about 200°. Initial impact points from propeller and left wingtip were about 75 feet from the main wreckage. The airplane came to rest inverted with the nose pointed upslope.
Medical and Pathological Information
An autopsy of the pilot was conducted by the Montana State Forensic Science Division. Toxicological screenings by the FAA Civil Aeromedical Institute (report #201500001001) were negative for carbon monoxide and ethanol; ibuprofen was detected in urine samples.
Tests and Research
Flight control continuity was established from cockpit to control surfaces. The engine remained attached; the case and accessories were deformed by impact. The right fuel tank was nearly full with fluid consistent with aviation fuel. The propeller remained attached; blades showed leading edge gouging, torsional twisting, chordwise striations, and trailing edge "S" bending, consistent with rotational forces at impact. No evidence of pre-impact mechanical malfunction or failure was found.
A Garmin Aera 796 GPS receiver in the wreckage contained 13 track logs from December 7 through the accident flight. Data showed the airplane departed Ronan at 1607; the last data point was recorded at 1619:19. After departure, the airplane turned west, climbed to 3,500 ft msl, then turned northwest. After a 360° turn, it proceeded southbound toward rising terrain. At 1619, at 3,450 ft msl, it began turning east. The track indicated maneuvering about 100 ft agl. The last data point at 1619:19 was about 3,765 ft west of the accident site, showing altitude 3,501 ft msl (100 ft agl) and ground speed 72 kts.