A Lucky Escape

When I first heard the details of the plane crash at Heathrow yesterday, my first thought was quite what a lucky escape everybody had. The flight was coming in from the east, so would have done the traditional run over central and west London known to so many people – indeed news reports last night were showing this YouTube video of the same approach, on the same kind of plane, to the same runway – which does go to show you quite how populated the areas under the approach actually are. The pilot yesterday managed to get the plane across the perimeter road, and although he hit the ground before the runway, it was within the airfield.

However, the big question now is what went wrong. Reports are saying that the pilot had told an airport worker that all the electronics had failed, and he had lost all power. That would have left the pilot with nothing but the emergency manual backup to the fully fly-by-wire systems to bring the plane in.

It also reminded me of comments that I heard from someone who worked for British Airways on aircraft maintenance for many years, finishing his career working on the 777 fleet, bemoaning the differences with the modern planes. On the older planes the mechanics that keep the whole thing going are fairly straightforward – there is a mechanical link between the pilots controls and the fundamental components that keep the plane in the air. With modern planes such as the 777, the links are electronic – essentially the pilot controls a computer which then controls the fundamental components, and the computer is essentially a black box. Fixing a fault involves removing one black box and putting in another – as he said, you can’t visually check the fundamentals, and you are essentially trusting in the skill of the electronics specialists that what is inside the black box does what it says.

Whilst it could be some sort of power system fault, some component having been improperly replaced, I really wouldn’t want to be a software engineer working at Boeing over the next few days. It definitely makes me glad that the bugs in my software are not a life or death situation like this…

heathrow plane crash 3 originally uploaded by artofthestate.

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