What happened
On 14 June 2017, a Piper PA-38-112 Tomahawk, registration G-BMVM, was performing a private flight from Brimpton Airfield to Thruxton Airfield. During the departure from Runway 25, the aircraft failed to accelerate sufficiently to reach the necessary rotation speed. As the takeoff roll progressed, the pilot noted that the airspeed was lower than expected at the runway's midpoint. The aircraft failed to achieve further acceleration and subsequently overran the end of the grass runway, coming to rest nose-down in a nearby crop field. The pilot, who was the sole occupant, sustained no injuries.
The investigation
The investigation examined the environmental conditions and the aircraft's performance capabilities. The pilot had noted gusty winds of 8 to 10 knots prior to departure and chose to avoid using a runway extension due to uncut grass and an upslope. A witness at the airfield observed that the wind direction was highly variable, shifting between 2/20º and 050º.
Post-accident performance calculations revealed that at maximum takeoff weight, the required distance for a grass runway would be 519 metres. The presence of a 5-knot tailwind would have extended this requirement to 621 metres. Although the aircraft was 190 lbs below its maximum weight, the available runway length of 520 metres was insufficient to guarantee safety under the prevailing wind conditions.
Findings
- The aircraft failed to reach takeoff speed because of insufficient acceleration caused by a potential tailwind component.
- Variable wind conditions likely resulted in a tailwind that increased the required takeoff distance beyond the available runway length.
- The aircraft sustained damage to the propeller, engine, fuselage, nosewheel, and wings.