Apparently …. the power failure affected both engines and occured as the plane was making its final approach towards Heathrow and was around a mile or two out.
It managed to squeeze itself over the perimeter fence and plopped down just short of the runway itself onto the rough grass and skidded to a halt …. stopping right on the edge of the tarmac bit.
The ”interesting” bit is that the southern runway approach takes the plane right over a heavily populated part of Feltham / Hounslow so if the pilot had NOT managed to trade off speed for height as he did – it would have crashed into this area and not only totalled the passengers and crew, but also would have made quite a mess of the local area – slightly to the detriment of the population.