jb747
Enthusiast
- Joined
- Mar 9, 2010
- Posts
- 13,002
In June 2011 I was on QF93 and a medical emergency 45 minutes after takeoff meant that we had to circle and dump fuel for I think 20 to 30 minutes (I'm sure JB would know exactly how long it takes), sadly I think the passenger died before landing in SYD. We were back on our way to LAX in less than an hour after landing in SYD.
You can land immediately if you really, really, want to. But that's for an aircraft emergency, and will require lots of checks for the overweight landing before it goes anywhere again. If you can get the landing weight down to less than 60 above the maximum, then, assuming you do the landing properly, there won't be any further delay.
The aircraft would have been at about 540 tonnes at take off. Max landing weight is 391. They'd have burnt about 20 tonnes before the turnaround, and would need to get rid of about another 70. So about 30 minutes. Advertised dump rate is 150,000 kgs/hr. There's about 80 tonnes that can't be dumped, so it's quite likely that you can't dump to max landing weight, even if that was the aim. As a contrast, you could dump just about everything in the 747.