What happened
On 27 June 2012, a Piper PA-34-200 Seneca, registration G-BBPX, was conducting a private flight from Newquay Airport to St Mary’s Airport in the Isles of Scilly. The flight, carrying one pilot and three passengers, arrived at St Mary’s during a period of marginal weather conditions.
Initially, the pilot attempted an NDB approach to Runway 14, but after losing visual contact with the runway threshold due to a fog bank, a go-around was performed. Seeking an alternative, the pilot identified that the south side of the airfield was clear and elected to land on Runway 27. Despite receiving wind information indicating an 8 to 10 kt tailwind, the pilot proceeded with the landing.
Upon touchdown at 75 kt, the aircraft began to decelerate. However, as the aircraft transitioned from the paved asphalt section to the grass portion of the runway, the braking effectiveness vanished. The aircraft failed to stop, overrunning the runway and striking a runway end light. The impact caused the left main landing gear leg to collapse, and the aircraft slid down the grass slope. All four occupants were able to exit the aircraft through the cabin door without injury.
The investigation
The AAIB investigation reviewed the pilot's report, air traffic control records, meteorological data, and radio transmission logs. The investigation examined the runway configuration at St Mary’s, noting that Runway 27 consists of both asphalt and grass, with a significant downward gradient at the end.
Investigators also analyzed the weather conditions at the time of the accident, which included scattered cloud at 200 ft and a surface wind of 140° at 16 kt. The investigation also considered the pilot's decision-making process regarding the landing parameters and the impact of the runway surface transition.