Originally Posted by
ivorget
If I'm not very mistaken it can't possibly be a TR failure as many are suggesting because G-VSKP was clockwise-rotored (tail-rotor on right, unlike G-LCFC which appears in some pics) and the spiral down was in the direction of TR being the main force. So as others have mentioned issues such as TR hardover or main rotor vortex ring state are possible.
Both ships have counter-clockwise turning rotors, the tail rotor type on the G-LCFC is a pusher and on G-VSKP was a puller.