Interestingly there was a similar accident in 2009. In that case a BA flight landed short of the runway at Heathrow. They decided in that case that it was due to a blocked fuel filter which had led to a sudden loss of power on the final approach. They fixed the problem for the future by redesigning the filter. Possibilities that come to find are 1. They haven't applied the repair to this plane 2. The crash investigators were mistaken about the cause of the accident and it was actually due to something else.