Accident Overview
On August 31, 2022, at about 1640 eastern daylight time, a Beech A36 airplane, registration N2270L, was substantially damaged in an accident near Houghton Lake, Michigan. The pilot and passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Flight Details
The pilot reported that the accident occurred during a two-leg cross-country flight. The airplane was fully fueled before the return leg. After takeoff, the pilot climbed to 9,000 ft mean sea level (msl) and proceeded direct to the destination under visual flight rules. Midway through the flight, the engine began "sputtering for a quick second" and subsequently lost power. The pilot attempted to restore engine power by adjusting the mixture, but these efforts were unsuccessful. The propeller continued to windmill during the gliding descent.
ADS-B Data
Automatic dependent surveillance – broadcast (ADS-B) data showed that the flight departed Cherry Capital Airport (TVC) in Traverse City, Michigan, about 1617, heading south-southeast toward Oakland County International Airport (PTK) in Pontiac, Michigan. The airplane reached an altitude of nearly 9,000 ft before entering a gradual descent. Around 1633, the flight track turned easterly, and the descent continued until the end of the available data. The final ADS-B data point was recorded at 1639:15 with an altitude of 1,825 ft. The pilot reported to a Federal Aviation Administration inspector that he switched fuel tanks approximately every 15 to 20 minutes during the flight, and that the last tank switch occurred about 5 minutes before the engine lost power.
Forced Landing and Damage
The pilot executed a forced landing to an open marsh area. The accident site was located about 0.4 mile beyond the final ADS-B data point at an elevation of about 1,130 ft. The fuselage nose forward of the firewall, including the engine, propeller, nose landing gear, and engine cowling, separated from the remainder of the airframe. The outboard portion of both wings and the inboard portion of the right wing were damaged.
Postaccident Examination
Postaccident examinations of the engine and airframe fuel system did not reveal any anomalies consistent with a loss of engine power. The engine exhibited internal continuity and compression at each cylinder. Both magnetos provided a spark across each ignition harness lead, and the engine-driven fuel pump was operational. The fuel system exhibited continuity from both wing roots to the engine fuel line at the firewall, and from both wing tanks to the corresponding wing root fuel inlet. The cockpit fuel selector operated normally during the exam. The left-wing fuel tank vent was clogged with dirt consistent with the accident sequence. The left-wing fuel vent orifice within the fuel tank bladder contained a small amount of debris; however, the vent was not fully obstructed and remained operational. The right-wing fuel vents were clear, and the tank bladder was intact. A total of 52 gallons of fuel was recovered from the airplane at the accident site. The airplane had a total fuel capacity of 80 gallons, of which 74 gallons were usable.
Engine Monitor Data
The airplane was equipped with an engine monitor that recorded oil temperature, fuel flow, exhaust gas temperatures (EGT), and cylinder head temperatures (CHT). The oil temperature appeared stable throughout the flight. EGT and CHT were stable and consistent during the initial portion of the flight. Fuel flow was steady at 17 to 18 gallons per hour until 1631:30, when it abruptly dropped to near zero and remained there for the duration of the available data. At that time, EGT increased briefly and then decreased abruptly. CHT decreased gradually beginning about one minute before the decrease in fuel flow, then decreased abruptly afterward. No other engine parameters such as engine speed or manifold pressure were available.