What happened
On 1 September 2011, an Aeronca 7ACA Champ, registration G-HAMP, was completing a local flight when the pilot decided to land at Lowfold Farm Airstrip in West Sussex. The airfield, which is aligned at approximately 020°, features a flat area near the threshold but otherwise slopes downhill. While pilots typically take off in a SW direction and land uphill, the pilot opted for a downhill landing into the wind.
During the approach, the wind strength had unexpectedly increased and the direction had veered. Although the windsock initially suggested the wind was blowing straight along the strip, its position became obscured during the final stages of the approach. As the aircraft neared the threshold, it encountered downdrafs caused by nearby trees. This resulted in a heavy three-point landing, causing the belly of the aircraft to strike the ground. The impact caused damage to the tailwheel spring, the belly fabric, and the propeller tips. There were no injuries to the pilot or the passenger.
The investigation
The investigation examined the environmental conditions and the aircraft's impact protection. The pilot had recently installed new seat cushions made from energy-absorbing foam. The pilot noted that these cushions might have prevented back injuries had the impact been more severe. The investigation also reviewed historical research from the Royal Air Force Institute of Aviation Medicine and the Defence Evaluation and Research Agency, which indicated that while conventional foam can increase spinal loads during vertical deceleration, energy-absorbing foam provides better protection against such forces.
Findings
- The aircraft encountered downdrafts from trees near the southern threshold during the approach.
- The wind direction had changed and increased in strength during the flight.
- The windsock was not visible during the final stages of the landing sequence.
- The landing was performed in a downhill direction into the wind.