What happened
On 21 August 2014, a Piper PA-32R-301 Saratoga SP, registration G-RIGH, was involved in a runway excursion at Strathallan Airfield in Perthshire. The aircraft, operated for private purposes, had recently refuelled at Cumbernauld. At the time of the incident, the airfield was experiencing a light crosswind following heavy rainfall, leaving the grass landing strip notably wet.
During the landing phase, the pilot experienced a significant float before the aircraft made contact with the ground. The touchdown occurred at a speed several knots above the target approach speed and at a considerable distance down the runway. Upon attempting to decelerate, the pilot found the braking action ineffective due to the slippery surface. Consequently, the aircraft failed to stop within the runway limits, exited the end of the strip, and crashed through a fence before coming to rest approximately 15 metres into an adjacent field. There were no injuries to the pilot.
The investigation
The investigation examined the aircraft's performance capabilities against the actual conditions on the day. The airfield features a 620 m grass strip with a slight 0.5% downward gradient toward the east. While manufacturer data suggests a standard landing distance of 479 m (including a ground roll of 309 m) for this model, the investigation noted that landing distances on short, wet grass can increase by as much as 60% according to CAA safety guidelines.
Investigators also considered the environmental factors, including the density altitude of approximately 1,300ft and the lack of a headwind, which contributed to the extended ground roll required to stop the aircraft.