What happened
While operating in low visibility, the flight crew emerged from a cloud layer at an altitude of roughly 250 feet above the ground. At this time, the aircraft was positioned slightly to the left of the runway centerline. During the transition, the non-flying pilot assumed control of the aircraft and attempted to correct the course toward the right.
Upon attempting this correction, the aircraft experienced a sudden, heavy roll to the right. When the pilot responded with a leftward correction, the aircraft reacted with an equally intense roll to the left. This sequence of uncontrollable rolling motions continued until the aircraft type impacted the terrain in a right-wing-low attitude. The impact resulted in substantial damage to the airframe.
Findings
Post-accident investigations identified technical irregularities within the yaw damper and the spoileron computer. While these malfunctions were present, the manufacturer noted that these specific anomalies were not sufficient to render the aircraft uncontrollable. Instead, the failures would have necessitated greater physical force and larger control wheel movements from the pilot to achieve the intended roll rate.
While the malfunctioning spoileron system would have increased the pilot's workload, particularly during periods of turbulence or crosswinds, the investigation found no other anomalies in the remaining flight systems. The uncontrollable rolling oscillations were the primary factor leading to the ground impact.