What happened
During a third training session for a pilot-under-instruction, a Cessna 340 departed for a flight involving single-engine maneuvers. While operating near the Richland airport, observers noted that the left propeller appeared to be rotating slowly. Witnesses described the aircraft entering a rapid, nose-down descent, with several noting the plane appeared to be in a spin. The aircraft struck the ground in a nearly vertical, nose-low orientation and was subsequently consumed by fire.
Findings
An investigation of the wreckage showed that the landing gear and flaps were retracted at the time of impact. The rudder trim tab was positioned with approximately 5 degrees of left trim. Post-crash analysis of the engines showed no evidence of mechanical failure prior to the accident. However, the left propeller was found in the feathered position, and power signatures were present on the right propeller blades. The pilot-under-instruction was flying with an expired medical certificate, while the pilot-in-command was an ATP pilot with 1,240 hours in this specific aircraft type. The investigation noted that the minimum control speed for single-engine operations (Vmca) is 82 KIAS, though the manual recommends a safer speed of 91 KIAS for training involving engine-out scenarios.