What happened
Following departure from runway 18R for a local flight, an air traffic controller notified the pilot of smoke visible from the left side of the multi-engine airplane. The pilot, who held a flight instructor certificate for single-engine aircraft, indicated an intention to address the issue and entered a left downwind pattern for runway 18R. After being cleared to land on runway 18L, the aircraft was observed on security footage trailing white smoke with the landing gear extended. During the approach, the aircraft entered a steep left turn with a bank angle exceeding 90 degrees, subsequently impacting the terrain in a near-vertical attitude just before the runway. The accident resulted in two fatalities.
Findings
Investigation of the wreckage indicated that the left engine's propeller was not being driven by the engine at the moment of impact, and the propeller was not in the feathered position. The landing gear remained extended, which, combined with the non-feathered propeller, significantly increased aerodynamic drag. While the right engine was operating at high power, the aircraft's airspeed likely dropped below the minimum controllable airspeed (Vmc). This loss of control was further exacerbated by the high bank angle required for the turn to the new runway. Although the white smoke was likely caused by an oil leak hitting hot engine components, the extent of the fire and impact damage prevented a definitive verification of the leak's source.