Beech M35 N9306Y accident near Tomball, Texas

Probable cause

A loss of engine power during cruise flight for undetermined reasons.

NTSB analysis

The pilot was conducting an aerial survey flight when the engine lost all power during cruise flight. The pilot was unable to restore engine power and he conducted a forced landing to a multi-lane highway. The airplane’s right main landing gear impacted the roof of a semi-trailer before the airplane rolled left wing down and descended into a concrete highway median. A postaccident fire ensued that destroyed most of the fuselage, cabin, and cockpit.

A comprehensive examination of the airplane’s fuel system was not possible due to extensive thermal damage sustained during the postaccident fire. About 25 gallons of fuel was reportedly recovered from the fuel system before the wreckage was moved, but the amount of fuel recovered from each fuel tank was not individually documented. Both left and right wingtip fuel tanks exhibited extensive thermal damage and no residual fuel was found within the wingtip tanks. Fuel drained from the fuel selector when it was removed from the wreckage. The airframe fuel filter contained 1/8 to 1/4 cup of fuel. The fuel strainer was largely unobstructed, with only minor debris present.

The airplane’s digital engine monitor was destroyed during the postaccident fire. Based on the pilot’s explanation of the fuel load, how the fuel was used during the flight, and a reported fuel consumption rate of 13.5 gallons per hour during cruise flight, there should have been ample fuel remaining to sustain normal engine operation. Examination of the engine did not reveal any preaccident mechanical malfunctions or failures that would have prevented normal operation. Ultimately, the investigation was unable to determine the reason for the loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN23LA088 for the full record.