CEN23FA074 · Beech M35

The pilot departed on the first leg of the trip with the airplane fully fueled and two passengers onboard. After about an hour flight, the pilot landed at the destination airport and dropped off both passengers. The airplane was not fueled at that time. The pilot departed as the sole occupant to return to the initial airport. About 18 miles from the destination airport, the airplane entered a gradual descent as it remained on course. About 6 minutes later, the airplane entered a descending left turn that continued until the available position data ended. The airplane impacted trees and terrain about 3 miles from the airport. The accident site was in a wooded area adjoining an open field. A witness heard the airplane as it approached and recalled that the engine sounded as if it was going to lose power but then “revved up really high.” This cycle occurred 3 or 4 times over a span of 10 – 15 seconds. The engine then seemed to stop; however, he was unsure if the airplane had descended behind a ridgeline. He did not hear the impact nor was he able to see the airplane. Postaccident airframe and engine examinations did not reveal any preaccident mechanical malfunctions or failures that would have precluded normal operation. The airplane was equipped with 2 25-gallon main fuel tanks and 2 10-gallon auxiliary fuel tanks. The fuel selector valve had settings for the left main tank, the right main tank, and the auxiliary tanks. The main fuel tanks were selected individually. Both auxiliary tanks fed simultaneously when selected. Excess (unburned) fuel from the engine was returned to the selected main fuel tank or, if the auxiliary tanks were selected, to the left main fuel tank. The fuel tank caps were securely installed, and each tank appeared to be intact. About 15 gallons and 10 gallons of fuel were recovered from the left and right main fuel tanks, respectively. Both the left and right auxiliary fuel tanks contained minimal fuel. Data recovered from an onboard electronic engine display unit revealed that the pilot departed on the initial leg of the trip with the left fuel main fuel tank selected. About midflight, the pilot changed to the auxiliary fuel tanks. Upon departure on the accident flight, the pilot had the right main fuel tank selected. About 14 minutes before the accident, the pilot selected the auxiliary fuel tanks to supply the engine. About 2 minutes before the accident, the useable fuel contained in the auxiliary tanks was exhausted, and the engine lost power due to fuel starvation. The pilot most likely selected the left main fuel tank in an effort to restore engine power. Useable fuel was available in both the left and right main fuel tanks when the engine lost power. The pilot was likely maneuvering toward an open field for a forced landing under a clear night sky and rising full moon. However, the airplane did not have sufficient altitude to reach the field. It could not be determined whether the night lighting conditions hindered the pilot’s attempted forced landing.

Verbatim NTSB analysis and probable cause from the NTSB dataset