AAIB investigation to Cessna 172S Skyhawk, G-ENNK
Flipped inverted following abandoned takeoff, Sherlowe Airstrip, Shropshire, 31 March 2016.
The pilot was attempting to take off from Sherlowe airstrip, using grass Runway 15 which is approximately 240 m long. However, he realised that the aircraft was not accelerating quickly enough to reach flying speed as the ground was too soft. He abandoned the takeoff and the aircraft ran off the end of the runway and into a soft, cultivated field where it flipped inverted.
The pilot was uninjured and evacuated the aircraft unaided. He stated that he regularly operated from Sherlowe airstrip and had calculated that Runway 15 gave a 40% margin for soft ground based on the performance figures for a short-field takeoff quoted in the Pilot’s Operating Handbook.
The Cessna 172S Pilot’s Operating Handbook (POH) shows that, for a short-field takeoff, the minimum ground roll required to lift off from a flat, level and dry paved surface is 186 m at 0ºC ambient temperature and 2,200 lb All-Up Weight. The POH notes that 15% should be added to the ground roll when operating from a dry grass runway which means that the minimum calculated ground roll is 214 m. There was thus a margin of 12% to offset against the soft, damp runway conditions.
The CAA’s Safety Sense leaflet 7c ‘Aircraft Performance’ contains a paragraph which urges pilots to establish a decision point at which takeoff can be safely abandoned without overrunning if a pilot is not happy with his aircraft’s or his engine’s performance.
A correction was issued concerning this Bulletin on 14 July 2016 amending the airfield name to Sherlowe, correcting the length of the runway and adding paragraph three.
Cessna 172S Skyhawk, G-ENNK Correction 08-16
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Published: 9 June 2016
Date of occurrence: 31 March 2016