What happened
On 3 January 2010, an Aviat A-1B Husky, registration G-HSKI, was performing a private flight when it encountered difficulties during landing at Llandegla Airfield, North Wales. While the weather conditions were clear and windless, the landing surface was covered in a significant layer of snow.
As the aircraft touched down on the private airstrip, the tailwheel configuration of the aircraft contributed to a nose-over event. The aircraft came to rest on its back. Both the pilot and the passenger were wearing full safety harnesses and were able to exit the aircraft through the right-hand door without sustaining any injuries. The accident resulted in damage to the propeller, the right wing, and the tail section.
The investigation
The investigation established that the airstrip was covered in approximately 10 inches of uncompact and loose snow. Although the pilot had successfully landed on similar snow-covered surfaces in the same location during the previous two weeks, those previous landings had occurred on much thinner, compacted snow, measuring roughly four inches in depth.
Prior to the flight, the pilot had been informed that snow had been present on the airstrip for approximately 10 days. It was expected that the weight of the snow would have caused it to compact over time; however, the investigation found that the surface remained deep and uncompacted, which led to the loss of control during the landing sequence.