History of Flight
On August 27, 2019, about 1835 Pacific daylight time, a Cessna 172 airplane, registration N4108F, was destroyed when it collided with terrain near McKenzie Bridge, Oregon. The pilot and the passenger were fatally injured. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91. The airplane owner stated that the pilot rented the airplane from 1730 to 1930 on the day of the accident. The owner warned the pilot before departure about high-density altitude and reduced airplane performance due to high ambient temperatures. The pilot’s exact departure time from Lebanon, Oregon (S30) was unknown.
A 16-second video from the pilot’s mobile phone, captured about 10 minutes before the accident, showed the airplane flying through mountainous terrain at a low altitude. Toward the end of the video, the airplane made a slight right turn, then immediately began a left turn, at which point the video ended. The engine sounded smooth and continuous.
Several witnesses near midfield at McKenzie Bridge State Airport (00S) observed the accident airplane. Two witnesses reported the airplane was about 5 ft above ground level (agl) flying east above runway 6 when it came into view. One witness heard no noise initially, then engine power increasing, with wingtips rocking. The airplane may have started to climb, then disappeared from view about 1–2 seconds later. A second witness heard the engine running, saw wings rock, then the airplane began a slow climb and disappeared behind trees about 15–20 ft agl. A third witness, a helicopter mechanic, said the airplane appeared slow and “way too low,” with engine continuous at low power. He saw the airplane bank hard side to side before it disappeared behind trees. About 15 minutes later, two witnesses saw smoke from the accident site.
Personnel Information
According to the pilot’s flight logbook, he began flight training in September 2018 and had 69.4 total flight hours by August 24, 2019, the final logbook entry. Most of his flight time was in the accident airplane make and model. The logbook contained no entries indicating experience with takeoffs and landings at mountain airports.
Meteorological Information
Local weather from a University of Utah website station about 3 nautical miles west of the accident site recorded at 1806: wind 2 mph with gusts to 8 mph from the northeast, temperature 98.4°F, dewpoint 41°F. The calculated density altitude at 00S was about 4,481 ft mean sea level at the time of the accident.
Wreckage and Impact Information
The airplane came to rest inverted in a wooded area about 615 ft east of the departure end of runway 6. The initial impact point (IIP) was marked by a tree about 120 ft tall with a severed top. A section of the left wingtip, found about 40 ft southwest of the IIP, displayed a depression in the leading edge. An intermediate impact point was noted along the debris path, marked by broken tree branches at the top of a tree about 120 ft tall, about 75 ft southeast of the IIP. The main wreckage was located about 150 ft from the IIP and was mostly consumed by postcrash fire, but comprised all major structural components.
Most flight control linkages remained attached to their respective control surfaces; control continuity was traced from rudder, elevator, and aileron to the cockpit. The elevator trim actuator measured 1.2 inches, consistent with a neutral trim setting. The propeller was thermally damaged and remained attached to the engine crankshaft. One propeller blade was separated near the blade root with a slight aft bend but no striations, nicks, or gouges; the other blade remained attached and undamaged. Rotational continuity of the engine and valvetrain could not be achieved due to postcrash fire damage to the crankcase and oil sump, but examination of crankshaft, camshaft, connecting rods, and pistons revealed no indications of catastrophic engine failure.
Medical and Pathological Information
An autopsy performed by the Oregon State Medical Examiner’s Office determined the pilot’s cause of death as blunt force injuries and immolation due to light plane crash. No significant natural disease was identified. Toxicological testing by the FAA’s Forensics Sciences Laboratory detected no evidence of ethanol or drugs of abuse in the pilot’s tissue samples.
Tests and Research
A postaccident weight and balance calculation used the pilot’s weight from his last medical exam (134 lbs), an estimated passenger weight (170 lbs), and fuel weight (108 lbs). The airplane’s gross weight was calculated to be about 1,700 lbs with a moment of about 66,000 inch-lbs, placing it within the utility envelope. Takeoff performance was calculated using the pilot’s operating handbook charts. Assuming flaps retracted and hard surface runway, at a field elevation of 5,000 ft and ambient temperature of 41°F, the airplane would have required a ground run of 744 ft and a total takeoff distance of about 1,330 ft to clear a 50-ft obstacle. At maximum gross weight of 2,200 lbs under the same conditions, the total takeoff distance would have been 2,455 ft.