On August 11, 2025, at 1130 Pacific daylight time, a De Havilland DHC-6-300, N344CS, was substantially damaged when it was involved in an accident at San Clemente Island, California. The 2 pilots and 16 passengers were not injured. The airplane was operated as a Code of Federal Regulations Title 14 Part 135 on-demand air taxi flight. According to the operator, the flight was uneventful until approximately 10 seconds prior to touchdown. About 15-20 ft above ground level and an airspeed of about 95 knots, the airplane began to yaw hard to the left and pitched nose down. The left wing struck the runway and the first officer, who was the pilot flying, banked to the right and the airplane touched down hard onto the runway. Upon touchdown, the captain took control of the airplane and tried to maintain directional control by using nosewheel steering, however, the airplane turned left and exited the runway surface. The airplane came to rest upright, the flight crew shut the engines down, and the occupants egressed from the airplane. About 1/3 of the outboard portion of the left wing and about 1/2 of the left aileron had separated. Postaccident examination of the airplane revealed the No. 1 (left) engine propeller beta ring was fragmented, with multiple pieces of the beta ring contained within the engine cowling. The airplane and the recovered beta ring fragments were retained for further examination.