Crab,
A maximum wind increase of 25 kt some 21 seconds after the helicopter applied 95% twin torque was recorded however at a data test point positioned where the Cessna would have passed over vehicle access road 'M'. This wind increase could best be described as a sudden gust.
I wonder what effect this might have on a Cessna 5-6 feet off the ground moving along at about 50 mph/kts or so with a nose high pitch attitude?
The AAIB puts off the wing dropping to the onset of a stall....could it have been the gust that upset the aircraft at that point?