What happened
Shortly after departing the runway, the pilot notified the flight service station of mechanical issues with the engines. Witnesses observed the aircraft type descending on a downwind pattern at approximately 300 feet while the pilot attempted to circle for runway 01. Passengers on board noted that the engines were operating with significant roughness and unevenness.
The aircraft eventually struck trees and a residence during its descent. The accident resulted in six fatalities, including the pilot and five passengers, while two passengers and two individuals on the ground sustained injuries.
Findings
Investigations into the mechanical state of the engines revealed significant failures. The right engine suffered from an extensive crack in the cylinder head and a partially disconnected intake pipe, which limited its output to only 55% of its rated power. Additionally, the left engine exhibited seven severely worn cam lobes. While the aircraft's weight and center of gravity were found to be more than the pilot had initially calculated, they remained within permissible operating limits.
Several human factors contributed to the accident. The investigation identified that the rudder trim was deflected fully to the left at the time of impact. Evidence also showed that the pilot had reduced power to the left engine, attempting to maintain flight using only the right engine. Furthermore, the crew's use of improper versions of company checklists and inadequate maintenance during 100-hour inspections were noted as contributing factors.