De Havilland DHC-6-300 runway excursion at San Clemente Island

No fatalities • San Celmente, CA, United States

A Twin Otter air taxi flight experienced a sudden left yaw and nose-down pitch during landing, resulting in a runway excursion and substantial aircraft damage.

What happened

On August 11, 2025, at 11:30 Pacific daylight time, a De Havilland DHC-6-300, registration N344CS, was involved in an accident at San Clemente Island, California. The aircraft was operating as a Part 135 on-demand air taxi flight carrying two pilots and 16 passengers.

The flight proceeded without incident until approximately 10 seconds before touchdown. While flying at an airspeed of roughly 95 knots and 15 to 20 feet above the ground, the aircraft experienced a hard left yaw and a nose-down pitch. The left wing made contact with the runway. The first officer, acting as the pilot flying, applied right bank to correct the movement, but the aircraft touched down heavily on the runway.

Following touchdown, the captain assumed control and attempted to maintain directional control using the nosewheel steering. Despite these efforts, the aircraft turned left and exited the runway surface. All 18 occupants were not injured. The aircraft sustained substantial damage, including the separation of approximately one-third of the outboard left wing and one-half of the left aileron.

The investigation

Post-accident examination of the aircraft identified that the No. 1 (left) engine propeller beta ring was fragmented. Multiple pieces of the beta ring were found inside the engine cowling. The aircraft and the recovered fragments of the beta ring were retained for further analysis.

Probable cause

Not determined

Frequently asked questions

What happened in the 11 Aug 2025 DE HAVILLAND DHC-6-300 accident near San Celmente, CA?

A Twin Otter air taxi flight experienced a sudden left yaw and nose-down pitch during landing, resulting in a runway excursion and substantial aircraft damage.

Were there any fatalities in the 11 Aug 2025 DE HAVILLAND DHC-6-300 accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 11 Aug 2025 involved a DE HAVILLAND DHC-6-300, registration N344CS, operated by Rampart Aviation, at San Celmente, CA.

What was the probable cause of the accident?

Not determined

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