N2270L

On August 31, 2022, about 1640 eastern daylight time, a Beech A36 airplane, N2270L, was substantially damaged when it was involved in an accident near Houghton Lake, Michigan. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that the accident occurred during a two-leg cross-country flight. The airplane was fully fueled before the return flight. After takeoff, he climbed to 9,000 ft msl and proceeded direct to the intended destination under visual flight rules. Midway through the flight, the engine began “sputtering for a quick second” and subsequently lost power. The pilot’s attempts to restore engine power, which included adjusting the mixture, were not successful. The propeller continued to windmill during the gliding descent.

Automatic dependent surveillance – broadcast (ADS-B) data revealed that the flight departed Cherry Capital Airport (TVC), Traverse City, Michigan, about 1617 and proceeded south-southeast toward Oakland County International Airport (PTK), Pontiac, Michigan. The airplane reached an altitude of nearly 9,000 ft before it entered a gradual descent. About 1633, the airplane flight track turned to an easterly course, and the descent continued until the end of the available data. The final data point was recorded at 1639:15 with a corresponding altitude of 1,825 ft. The pilot reported to a Federal Aviation Administration inspector that he switched fuel tanks about every 15 to 20 minutes during the flight, and that he had last switched fuel tanks about 5 minutes before the engine lost power.

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, was separated from the remainder of the airframe. The outboard portion of both wings and the inboard portion of the right wing were damaged.

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.

The airplane was equipped with an engine monitor that recorded oil temperature, fuel flow, exhaust gas temperatures, and cylinder head temperatures. The oil temperature appeared stable throughout the flight. The exhaust gas and cylinder head temperatures were stable and consistent during the initial portion of the flight. The fuel flow was steady at 17 to 18 gph until 1631:30 when it abruptly dropped to near zero and remained there for the duration of the available data. At that time, the exhaust gas temperatures increased briefly and then decreased abruptly. The cylinder head temperatures decreased gradually beginning about one minute before the decrease in fuel flow. Afterward, they decreased abruptly. No other engine parameters such as engine speed or manifold pressure were available.