CEN21LA401

The pilot and passenger were conducting a local personal flight in the experimental amateur-built airplane. While on the base leg of the traffic pattern, the engine’s drive belt failed and was ejected from the airplane. During the ensuing forced landing, the pilot allowed the airspeed to decay, and the airplane experienced an aerodynamic stall and descended into trees, which resulted in substantial damage to the wings, fuselage, and empennage. The airplane’s maintenance records revealed that the drive belt was last replaced about 20 years ago. The pilot had completed a maintenance inspection about 2 months before the accident and a preflight inspection before the flight; he did not notice anything wrong with the drive belt during the inspections. There were no other mechanical malfunctions or anomalies with the airplane that would have precluded normal operation.

On September 6, 2021, about 1030 central daylight time, an experimental amateur-built Genesis light sport airplane, N105BJ, was substantially damaged when it was involved in an accident near Fairmont, Minnesota. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he originally built the airplane and was the only owner. On the accident flight, the airplane was on the base leg of the traffic pattern when he heard a loud “bang” and the engine “sped up.” He suspected that the engine drive belt had failed, and he shut down the engine. During the ensuing forced landing, the pilot allowed the airspeed to decay, and the airplane experienced an aerodynamic stall and descended into trees, which resulted in substantial damage to the wings, fuselage, and empennage. The airplane came to rest in the trees about 40 ft high. The pilot and passenger egressed from the airplane and climbed down the trees. The pilot later stated that the engine’s drive belt had failed in flight. He further stated that he had looked at the belt during the preflight inspection and did not notice anything wrong with it. The pilot reported that he had completed a maintenance inspection on the airplane on July 10, 2021. The pilot recommended that to prevent this accident he could “check the belt more closely.” After the airplane was recovered from the trees, Federal Aviation Administration (FAA) inspectors completed an examination. They stated that there was no drive belt found on the engine. The airplane’s maintenance records revealed that the drive belt was last replaced about 20 years ago, which was confirmed by the pilot. There were no other mechanical malfunctions or anomalies found with the airplane that would have precluded normal operation. The new owner of the kit manufacturer, Slipstream, did not have an interval time for the drive belt replacement.