AAIB investigation to Kolb Twinstar MkIII Twinstar, G-MZGJ

Forced landing after control restriction near Otherton Airfield on 10 March 2015.


Following departure from Runway 25 at Otherton Airfield, the pilot encountered a control restriction in pitch during a shallow left turn at approximately 450 ft. The aircraft began to descend and altitude could not be maintained. The pilot initiated a forced landing but during the latter stages of the approach, the left wheel struck a wooden post, yawing the aircraft to the left. The left leg dug into the ground and the aircraft slewed to the left before skidding to rest after approximately 15m. The pilot and passenger were uninjured.

The pilot reported that he had performed a control check prior to takeoff, with no anomalies and the restriction was no longer apparent after the forced landing. The aircraft was examined by the Light Aircraft Association (LAA), who concluded that the control restriction was probably caused by excess slack in the elevator control cables allowing contact with the tail boom. Bulky clothing may have exacerbated the effect by pushing a turnbuckle into the side of the boom, thereby causing a temporary restriction.

The LAA advise they will write to UK-registered Twinstar owners, reminding them of the importance of maintaining correct cable tensions and the risk of clothing impinging on controls.

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Kolb Twinstar MkIII Twinstar, G-MZGJ 08-08

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Published 13 August 2015