20240408003909A

On April 8, 2024, at 1400 CST, a twin-engine Temco D-16A (“twin navion”), serial number: TTN-65, sustained substantial damage when it impacted trees in a wooded area shortly after takeoff from Clarksville Municipal Airport, AR (H35). The pilot in command (PIC) and three passengers sustained minor injuries. The airplane was operating as a part 91 personal flight.

On April 9, 2024, FAA inspector (iic) arrived on scene to begin the investigation. The aircraft came to rest on its belly with the cockpit area intact. The nose of the aircraft was ripped off and the tail was deformed to the left. The wings were damaged but attached. The left tip-tank was attached but the right tip-tank was separated from the wing.

The left engine separated from the aircraft and came to rest about 6 feet from left wing. One of the two blades on the left propeller assembly was in the vertical position, leading edge free of defect, and slightly deformed. The second blade on the left propeller was folded under the engine but had no/little twist. Damage to the left propeller was consistent with a no torque/no power/no rotation condition. The right engine was partially separated but still attached to the wing. Both blades on the right propeller exhibited significant leading edge damage, twist, and curling – all evidence that the right propeller was powered and producing significant thrust upon impact.

The left nacelle fuel tank appeared empty and the fuel bladder appeared intact and relatively undamaged with no signs of fuel leaking. The main tank was visually checked and looked to be filled up to about 3/4 of the tank.

In the cockpit, the throttle and propeller levers were pushed to forward limit and mixture was in “idle cutoff”.

The right fuel selector was set to the right nacelle tank and the left fuel selector was set to left nacelle tank. The crossfeed was selected “on”.

FAA iic interviewed PIC. PIC stated the left and right fuel selectors were set to the main tank and startup and taxi were uneventful. However, within seconds of lifting off, PIC lost power to the left engine and the aircraft began slow descending left turn. PIC attempted to restart the engine but was unsuccessful. Aircraft ultimately impacted trees and crashed.

Video taken by the aft right seat passenger captured the sequence of events and shows right engine RPM stable throughout the event while left engine RPM was erratic and trailing right engine by as much as 1,000 RPM. The left fuel pressure also shows erratic indications and at the red (or zero pressure) line during the time of the power loss.

On may 7, 2024, FAA iic conducted on-aircraft inspection to determining any mechanical cause of the left engine failure.

The left nacelle tank bladder was filled with water and checked for leaks. The left electric boost pump was operationally checked and operated as designed. The left gascolator and left carburetor contained residual amounts of fuel. Gascolator fuel screen appeared clean and unobstructed. Left propeller was removed and the engine was successfully started and run - ruling out mechanical engine failure.

On-scene evidence, PIC statement, video footage, and on-aircraft inspection rule out mechanical defect and point to a fuel starvation event brought on by poor fuel management due to pilot error.

PIC stated he believed the fuel selectors we set to the main tanks. The main tank position is 180 degrees from the nacelle tank position and easily confused. Evidence points to the PIC mistakenly selected the nacelle tanks when he thought he was selecting the main tanks.