What happened
On 24 June 2007, a Piper PA-38-112 Tomahawk, registration G-OLFC, was performing a private takeoff from a grass runway at Ashcroft, a private airstrip in Cheshire. After assessing the runway surface as dry and suitable, the pilot conducted power checks and prepared for departure. During the takeoff roll, the pilot followed a technique of rotating at minimum speed and maintaining the aircraft in ground effect to reach a climb speed of 61 kt.
As the aircraft approached a four-foot high fence at the end of the runway, the pilot increased the climb attitude. During this maneuver, the underside of the rear fuselage made contact with the fence. This impact caused the aircraft to pitch nose-down, leading the nosewheel to strike the ground and collapse. The aircraft subsequently pitched further down and came to rest inverted in a field. The pilot, who was wearing a full harness, escaped the wreckage without injury.
The investigation
The investigation examined the takeoff performance and the runway conditions. An eyewitness noted that the aircraft's acceleration appeared slow and that the aircraft adopted a high nose-up attitude shortly before the impact.
The pilot's prior calculations for takeoff performance had estimated a required distance of 537 m to clear a 50 ft obstacle, based on a maximum takeoff weight and a safety factor. However, the investigation noted that the pilot had not included the 5% additional distance recommended by the CAA Change Sheet for performance writedown. Furthermore, there were questions regarding the actual length of the runway, as the declared 550 m length was based on information provided by previous owners and was subject to re-measurement.
Findings
- The tail of the G-OLFC struck a fence at the end of the runway.
- The impact caused the nosewheel to collapse and the aircraft to land inverted.
- The pilot may have misjudged the transition from level acceleration to a climb attitude while concentrating on the approaching fence.
- The aircraft's actual performance may have been lower than calculated due to a lower headwind or potential braking drag.
- The pilot's takeoff calculations failed to incorporate the CAA-recommended 5% performance writedown.