What happened
On 16 May 2018, a Piper PA-3RE-301T Saratoga, registration N517FD, was performing a private flight to Fair Isle Airfield in the Shetland Islands. The aircraft, carrying one pilot and five passengers, arrived at the airfield following a flight from Retford/Gamston Airfield.
During the final approach to Runway 24, the pilot encountered sudden windshear. An initial updraft and increased headwind caused the aircraft to balloon, prompting a reduction in power. This was immediately followed by a downdraught and a loss of headwind, forcing the pilot to apply significant power to maintain the approach path. While the pilot successfully achieved the intended touchdown point, the windshear had resulted in a touchdown speed much higher than planned.
As the aircraft rolled along the gravel runway, the pilot noted the high groundspeed but opted to continue the landing rather than performing a go-around. The aircraft proceeded toward the upwind end of the runway, where the terrain slopes downward. While attempting a 180-degree turn at the end of the runway, the aircraft encountered loose gravel and a sloping surface, causing it to slide sideways off the prepared area. The impact resulted in the partial collapse of the right main landing gear and damage to the right stabilator and rear fuselage.
The investigation
The investigation examined the pilot's approach and the aircraft's performance calculations. It was established that the pilot relied on performance data for a level, paved runway rather than the specific requirements for a gravel surface. Furthermore, the pilot focused on the ground roll distance from touchdown rather than the landing distance required from 50 feet above the threshold. The investigation also reviewed the impact of the local topography and wind conditions on the aircraft's deceleration capabilities.