Background
Halfpenny Green airfield features three asphalt landing strips and an airship mooring post. Runway 28 is 775 meters long, while Runway 34 offers a landing distance available of 1,000 meters and a total length of 1,195 meters. The airship mooring post is located south of Runway 28 near the control tower and hangars. On the day of the incident, weather conditions were fine with a surface wind from 240° to 260° at between 5 and 15 knots.
Sequence of Events
The pilot of G-BSIB, a Piper PA-28-161 (1980 model, Lycoming O-320-D3G engine), was returning from a navigation exercise. At approximately 1210 hours, he requested joining instructions. Initially, Runway 28 was active, but an airship was landing, so he was instructed to join the circuit for Runway 34. By the time the aircraft was overhead, the airship had vacated Runway 28, and the pilot was invited to land on that runway. However, two other aircraft were in the vicinity. The pilot was uncertain of their positions but was confident the approach to Runway 34 was clear; he elected to continue his approach to Runway 34.
This runway change resulted in a crosswind component of 5 to 15 knots with a possible slight tailwind component. The pilot approached Runway 34 high and fast. The aircraft floated for a prolonged period and touched down well beyond the midpoint of the runway. Despite heavy braking, the aircraft ran off the end of the runway, penetrated a post and wire fence, and came to rest embedded in the airfield boundary hedge. The pilot, anticipating the collision, switched off the magnetos and engine fuel supply. Both occupants were unhurt and vacated the aircraft unaided through the normal exit door.
Aftermath and Comments
The pilot generally agreed with the CFI's assessment of events but believed that after his 'finals' RTF call, the AFISO had informed him of the surface wind as 260°/15 knots. However, the supervising AFISO stated that the wind information given was 230° at 10 knots. The AFISO observed the aircraft very high on a steep approach and noted it floated for some time above the runway. Realizing it would not stop on the runway, he sounded the crash alarm before touchdown.
The CFI expressed concern about the safety implications of a new fence in the overrun area of Runway 22, which is only 640 meters long and slopes downward. This fence, supported by concrete posts, was considered less forgiving than the 8-inch diameter wooden post that G-BSIB struck, which snapped and detached the left wing. The CFI also suggested relocating the airfield windsock nearer the center.
Airfield management explained that the new fence needed to be substantial due to a public road immediately beyond it, and the CAA had not objected to its design. Additionally, while the UKAIP for Halfpenny Green dated 17 December 1998 shows the windsock in the central area, this is incorrect; the windsock had been sited near the airfield perimeter for some time to keep the central area clear for para-dropping.