EGLL 27L: 3660m
Landing distance for an HS125 approx 1000m from touchdown. (guess
)
Overfly the a/c at 400', gives a 3 degree slope of 1.33 Nm/2,470m to touchdown.
3660-2470 = 1190m to stop.
In a 125, you don't have to directly overfly, ye gods, you might even do some of that pilot stuff and manouevre!
Sometimes, I think I know why the NIMBYs and lawyers can run the place
