What happened
On 11 June 2014, a Vans RV-7, registration HB-YLM, was conducting a private flight over Loch Ness in favorable weather conditions. While cruising at 2,000 ft, the pilot noted that the engine had started running roughly. Using GPS navigation, the pilot located a farm airstrip situated near Fort Augustus, Inverness-shire, and performed a successful precautionary landing.
Following the landing, the pilot conducted inspections of the fuel and carburetion systems. These checks, including a fuel sample analysis, revealed no defects, and the engine continued to operate normally during ground runs at full throttle. The pilot subsequently attempted a departure from the airstrip.
During the takeoff roll, the aircraft began drifting toward the left side of the strip, which was covered in damp grass. Despite attempts to use rudder input to maintain the centerline, the deviation continued. The pilot reduced power to idle to abort the takeoff, at which point the left wing collided with a fence post. This impact caused the aircraft to yaw further left, resulting in the right wing also striking a fence post before the aircraft finally came to a halt.
The investigation
The investigation examined the circumstances surrounding the engine roughness and the subsequent loss of directional control. Investigators reviewed the pilot's post-landing inspections, which had failed to identify any mechanical or fuel-related issues. The condition of the airstrip surface, specifically the presence of damp grass, was also assessed in relation to the aircraft's handling during the takeoff roll.