Based on JB's comments earlier, a 747 can dump fuel and always then be under max landing weight, so it can land pretty much immediately. Whereas an A380 can only dump some of its fuel and will therefore still be well above max landing weight, especially if the dump occurs early in the flight.
So, if the situation is:
* 747 can dump fuel and land straight away
* 380 can dump fuel and still need to fly for up to 4 hours before being under max landing weight
- then I think it's pretty clear which is the better-designed and safer aircraft!!
I certainly would prefer to be on an aircraft which can dump fuel and land straight away if needed, rather than dump fuel and have to continue flying for 4 hours to get below max landing weight!
John, you're going to have to start picking your aircraft carefully. Many of the smaller aircraft cannot dump fuel at all, and not just Airbus....
A fuel dump takes time. In a 747 you'll be looking at about an hour for the dump to get you from max take off weight, to max landing weight. Add some time for the initial problem to become evident, and then time for the approach and landing ('cos you can't normally just turn the dump off as you arrive on the ILS .... although that has been done in serious cases), and you're looking at a minimum flight time of 2 hours. Bear in mind too, that in some cases you cannot return to the place you took off from (because take off mimina is often better than landing minima). Of course, it's also quite possible that you'll really need to dump to well below max landing weight (wet runway). For instance, not a medical emergency, but QF30 was dumped to 40 tonnes BELOW max landing weight. As a general rule though, the 747s are not landed above max landing weight....unless there is an overwhelming emergency. That does not include medical at all....
Airbus on the other hand do treat it differently. Their treatment of 'max landing weight' is less rigid. They allow a dump to a point at which the weight is 'reasonable', even though above the max, and are not too fussed if you then land. There may be other issues that preclude you doing so, but generally, you can. With a smooth touchdown, and low levels of braking, there may be no inspections required at all. Autoland is mandatory for this though, which may be a limit in its own right.
The civil aviation authorities then step into the act, with their own interpretation of how max weights are to be handled. For Australian registered aircraft, you MUST declare an emergency to allow an overweight landing. Rather timely perhaps, but they have, in the last few days, released an exemption to this requirement for the A330 and A380.
With regards to certification, returns for an ill passenger simply are not considered. You can always come up with scenarios that you may think should have been looked at, but honestly, if certification considered everything that could ever happen, nothing would ever fly.
All of these aircraft can take off, turn around and land again
immediately. Without any fuel dump, at vast weights above the maximum. And old rule of thumb is that any runway you can take off from, you can immediately return to. You will, of course, blow tyres, but you will stop. But, if you then want to add system failures on top of that, it's very easy to build a scenario on which you'll need Edwards AFB to be able to land.
The question it all comes to in the end though, is what level of risk the captain will accept to get your sick passenger onto the ground. In the right weather conditions, even if weight were not an issue, there will be innumerable airports that you would fly past. Go to Europe in winter, and a large number of the diversion airports are available only for major aircraft problems. They will not be considered at all for medical issues...and this applies to the 747/777 as well.
As I said near the start of this thread, the answers to this sort of problem are not black and white. They will vary dramatically depending upon a whole range of factors, most of which, none of the passengers are even slightly aware of.
So, I guess the $64,000 answer is 'what would I have done'? Well, recognise straight away that this is conjecture, and I have no knowledge other than what the media printed as to the actual facts. Initially I would have continued along the flight planned track (away from Singapore). Medical advice on board would have been solicited (as it was), but also Medlink would have been called on the satphone. Medlink's decision with regard to the desirability of getting the passenger on the ground or not, and where, would have been taken as being the 'medical position'. If their call was to land with Singapore being the best medical choice (as it surely would have been), then the dump would have been commenced, and the aircraft simultaneously would have been descended to the lowest level within the controlled airspace. Speed brake would have been selected against power (and even the landing gear later on) to increase the fuel consumption to the maximum possible. The aircraft would have been landed overweight at the end of the dump. Crew would be out of hours to continue, so pax and crew go to hotels.
If it happened a bit later, the options are actually a little better. Dubai is a LONG way from the planned route, but if you had the problem come up around the Indian coastline, you would have sufficient time to arrange to track via the gulf. Because no backtracking is involved, and you still have about 4 hours to run (in either direction), you could dump and probably get close to max landing weight. If you can get below it, there would be no inspections, and you would be able to continue the flight (hours would most likely not become an issue) to Europe.
If Medlink did not agree with the passenger's assessment, the flight would have continued to destination.
