Accident Summary
On the day of the accident, a certified flight instructor (CFI) was scheduled to conduct an instructional flight. During a weather briefing, the CFI informed the flight service station specialist that the flight plan included engine-out practice. After takeoff, while climbing through about 100 feet of altitude, witnesses observed the aircraft roll sharply to the right and pitch nose-down. The aircraft subsequently struck the ground in an inverted attitude, with the left propeller and left wing tip making initial contact. All three occupants on board were killed.
Investigation Findings
Post-accident examination of the aircraft focused on the power lever of the right engine. Laboratory analysis revealed that the lower aft part of the lift gate detent was worn. This wear created a ramping effect between the rounded edge of the lift gate and the flight idle stop. According to the investigation, a worn lift gate detent would allow the power lever to be inadvertently moved into the beta range. Such movement could generate asymmetrical drag and degrade airplane performance, particularly during critical phases of flight such as takeoff and initial climb.
The official probable cause findings identified three occurrences. The first was a total loss of engine power due to mechanical failure or malfunction during takeoff initial climb. Specific factors included that one engine was involved, that the pilot in command (the CFI) was performing a simulated emergency procedure, and that the throttle/power lever was worn, causing the propeller reversing system to deploy inadvertently. The second occurrence was a loss of control in flight during the same phase. The third was an in-flight collision with terrain during an uncontrolled descent.
Probable Cause
The official probable cause is a loss of engine power (total) due to mechanical failure/malfunction during takeoff initial climb. Contributing findings: the throttle/power lever was worn, leading to inadvertent deployment of the propeller reversing system; and a simulated emergency procedure was being conducted by the pilot in command.