NTSB

Probable cause: The flight instructor’s inadequate in-flight fuel management, which resulted in fuel starvation and a total loss of engine power. 

Probable cause: The loss of yaw control due to an inadequately compressed rudder swage, which resulted from inadequate maintenance and led to the separation of the forward right rudder cable.

Probable cause: A total loss of engine power for reasons that could not be determined based on the available evidence. 

Probable cause: The pilot’s failure to identify the alternate runway, to perform a timely precautionary landing, and to maintain airplane control. Contributing to the accident was the failure of the left engine due to oil starvation for reasons that could not be determined based on the postaccident examination.

Probable cause: The pilot’s failure to maintain airplane control during an attempted go-around in gusting crosswind conditions, which resulted in an exceedance of the airplane’s critical angle of attack and a subsequent aerodynamic stall.

Probable cause: The pilot’s decision to continue visual flight rules flight into instrument meteorological conditions, which resulted in controlled flight into mountainous terrain.

Probable cause: The pilot’s impairment, due to his use of a combination of psychoactive drugs and a vision deficiency in his left eye, which resulted in a failure to maintain adequate altitude during final approach to landing and subsequent collision with power lines.

Probable cause: The pilot’s loss of control after exceeding the airplane’s critical angle of attack during takeoff, which resulted in an aerodynamic stall.

Probable cause: The flying pilot’s excessive maneuvering of the airplane at a slow airspeed, which resulted in exceedance of the critical angle of attack and an aerodynamic stall. Contributing to the accident was the pilots’ operation of the airplane over its maximum allowable gross weight.