History of the Flight
The aircraft, a Piper PA-28-181 registered G-BOXY, was operated by a flying club for a trial lesson. The instructor refuelled the aircraft to half-full tanks before the flight. The weather was fine with a surface wind of approximately 150°/7 kt. Runway 24, a grass runway with a take-off run available of 488 metres and an upslope of 1.9%, was in use. The instructor briefed the student and two passengers on safety harnesses and emergency egress. No weight and balance calculations were performed. The pilot used flap 10° for take-off with a rotation speed of 55 kt. The aircraft accelerated normally, but after becoming airborne it failed to climb above a few feet. As the perimeter hedge approached, the pilot pitched nose-up; the stall warning sounded and the right wing dropped slightly. The pilot closed the throttle and landed straight ahead in a sugar beet field about 180 metres beyond the runway end. The aircraft sustained minor damage to a nosewheel spat.
Post-Incident Examination
Initial examination found no major fault with the engine. A subsequent flight test conducted in accordance with the CAA Airworthiness Flight Test Schedule showed the aircraft performed within published figures. A video recording taken by a passenger was analysed; the audio frequency spectrum indicated engine RPM remained constant at approximately 2,340 RPM from take-off roll until the stall warning sounded.
Performance Analysis
Occupant weight was estimated at 355 kg; fuel weight was estimated at 65 kg. The aircraft's basic empty weight was 720 kg, giving a total take-off weight of 1,140 kg, below the maximum of 1,160 kg. The Pilot's Operating Handbook does not provide performance data for flap 10°, but data for flap 0° and flap 25° are given. Using CAA factors for grass surface and slope, the factored take-off distance to 50 feet was calculated as 803 metres for flap 0° and 711 metres for flap 25°, both exceeding the 488-metre runway. Applying a safety factor of 1.33, the distances increased to 1,067 and 945 metres respectively. Ground roll calculations gave factored distances of 587 metres (flap 0°) and 512 metres (flap 25°), also exceeding the available runway length.
Organisational Aspects
Netherthorpe is a licensed airfield with one of the shortest take-off and landing distances in the UK. The flying club provided no written performance guidance; it relied on the commander's responsibility to ensure adequate performance. The CAA's Safety Sense leaflet states that the pilot in command must ensure aircraft performance is adequate, but notes it may not be necessary to check data before every flight if runway length is obviously sufficient.
Discussion
The post-incident flight test and video analysis indicated that an engine malfunction was unlikely. Performance data factored according to CAA recommendations showed that insufficient take-off run was available for the aircraft to become safely airborne and clear the perimeter hedge. Ultimate responsibility rests with the commander, but the club environment should provide guidance, particularly on performance factors, flap settings, and passenger carriage.