- Oct 29, 2006
He doesn’t really have to request one. A twin engined aircraft with an engine out is in an emergency situation, at which point all of the rules go out the window. On the other hand, telling ATC that you are going to dump shouldn’t be an issue.
If I recall correctly the recommended minimum for dumping is 6,000’. Any emergency over-rules that. The rules are fading - probably ‘cos I’m not looking at them any more.
We don’t really know just what the aircraft issue and status was. The engine was apparently compressor stalling, which almost certainly means that it’s physically damaged, most likely having thrown/eaten blades. It’s unlikely to have been a clean shutdown (of the sort you’d get with loss of the mechanical fuel pump).
There’s a balance to be struck here somewhere. Whilst the aircraft is certified by the FAA and Boeing (both of whom we trust) for a very long ETOPS period (5 hours or so) that does not mean that flying around on one engine for any longer than you have to is a good idea. So, back on the ground as soon as reasonably possible. Conversely, dumping takes time. You don’t really need to get the aircraft to MLW, but the closer you can get to there the better.
As for dumping over land, any scenario in which you want it on the ground ASAP, for instance a cargo fire with confirmation, would have me ignoring all of the rules. I’d stop the dump at around the start of finals. In that case I’m getting rid of as much weight as I can, as I want the quickest stop I can manage, so that I get people running away. If QF 30 had approached over land I would have continued the dump irrespective, as I wanted it on the ground ASAP and at as light a weight as possible.
Was it a mistake? On the very limited info we have, I don’t see the need for the hurry, so I’d say yes. Let’s see if that opinion survives a bit more information.
So if the aircraft is too heavy, what's the impact? Won't slow down in time on landing?