What happened
During a scheduled maintenance test flight following the replacement of both engines, an aircraft entered an uncontrolled descent. According to eyewitness accounts, the takeoff roll and the initial climb phase proceeded without apparent issue. However, upon reaching an altitude of approximately 500 feet, the aircraft began a right-hand bank. This maneuver intensified until the wings reached a vertical position, at which point the nose dropped.
The aircraft struck the ground in a steep, nose-down, inverted attitude. At the time of the impact, the landing gear was retracted, and the left spoiler had been deployed. All three fatalities occurred during the accident.
Findings
Post-accident examination of the wreckage showed that the right engine had been feathered and secured. Investigators found no evidence of a malfunction or failure within the airframe systems or either engine prior to the impact. While the continuity of the engine mounting and rigging could not be verified due to the extent of the impact damage, no pre-impact mechanical failures were identified.
Data indicated that the rudder trim was in a neutral position. It was noted that the pilot, who was a principal in the operating company rather than a regular line pilot, had been trained in emergency procedures that involve using rudder trim immediately following an engine failure to prevent the deployment of spoilers. The investigation did not find evidence of engine failure, yet the aircraft's flight path transitioned into a fatal roll.