Singapore Airshow 2010

[Reuben65]

All aircraft are certified to land at their max landing weight. Instances which they might have to do so would be dire emergencies like smoke or fire, especially right after take-off, when they have to land ASAP. If time is not critical, they can fart off somewhere and sort out their emergency and check-lists, with fuel dumping as a consideration. With current high fuel prices, sometimes it may be more viable to land over-weight, and conduct over-weight landing checks by engineers thereafter.It is completely safe to do so.

[Vortices]

Fuel dump is neccessary for a few reasons, for combat like the tornado, it purges its fin of any fuel prior to engaging as it is a big target, landing (emergency or ortherwise) as for most aircraft, Max take off weight and Max Landing weight is very different.

It is true, the f-111 is a heavy aircraft, it is actually one of the more interesting story in American military aviation development. It is an example of how things can go horribly wrong.

http://airplanedevelopmentstories.blogspot.com/2007/03/tfxf111-page-2.html

Thanks to the mess up, we got the f-14, something good did come out of it.

[Reuben65]

Thanks Vortices....yes, max take-off and max landing weight are indeed different. Before an aircraft is dispatched for flight(esp in a commercial aircraft), the Regulated Take-off Weight is a combination of factors. I will not elaborate, as it can be quite tedious. In any case, the aircraft will be dispatched with the most limiting weight, which still is safe to land in an over-weight situation, with post over-weight landing checks by engineers thereafter..To dump fuel amounting to many tonnes may take a long time. In times of critical emergencies, time is not a luxury, putting the aircraft on the ground is the priority, thus an over-weight landing is the only option.

[Vortices]

Thanks Rueben for the info.
With some aeroplane, on heavy take off, even with max jettison, the aircraft is still above Max landing, overweight landing is the only option.
Happy New Year...Gon xi fa chai.

[renold]

Thanks Vortices....yes, max take-off and max landing weight are indeed different. Before an aircraft is dispatched for flight(esp in a commercial aircraft), the Regulated Take-off Weight is a combination of factors. I will not elaborate, as it can be quite tedious. In any case, the aircraft will be dispatched with the most limiting weight, which still is safe to land in an over-weight situation, with post over-weight landing checks by engineers thereafter..To dump fuel amounting to many tonnes may take a long time. In times of critical emergencies, time is not a luxury, putting the aircraft on the ground is the priority, thus an over-weight landing is the only option.

Thanks for the enlightenments. It would be a good topic and some thing to think off, after visited the Air Show. Hence make the ticket $$ worth.

Still not explain why the F111 with that burning feature. If it is due to max landing weight issue, then what happen if the F111 return with bombs that not released; due to some reason. May be bombs weight less .... Do other war planes have the same feature?

[Reuben65]

Hi Reynold,
I'm not too sure about the flame burning feature of the F111 to dump excess fuel. The F5E burns 10,000lbs per hour at FULL after-burner. Looking at the
F111 pics, I cannot deduce if it is a fuel-dumping feature. (any fighter jocks care to share?). As for the bomb issue, again the aircraft is designed to land over-weight. The problem arise when you have a single-engine failure, and you cannot maintain altitude. The engines are designed to operate at MAX power for a certain time only, otherwise you will over-cook it and it may seize on you. So, to maintain controllability, you need to lighten your aircraft. If even by dumping fuel( Better be close to airport/ airbase), you still cannot maintain flight parameters, you can jettison the ordnance as well. The remaining ordnance can be dis-armed upon landing at designated areas.

[Reuben65]

And in most, if not in all cases, fighters do not have very long range by itself. To extend its range, they carry drop tanks or do air-to-air re-fuelling. So, when the need arises, they jettison the drop-tanks for manoeuvrability, and re-org with a tanker to re-fuel, and either continue the mission or return-to-base. Hope this helps.

[renold]

And in most, if not in all cases, fighters do not have very long range by itself. To extend its range, they carry drop tanks or do air-to-air re-fuelling. So, when the need arises, they jettison the drop-tanks for manoeuvrability, and re-org with a tanker to re-fuel, and either continue the mission or return-to-base. Hope this helps.

Thanks Reuben. Good feedback.

[Reuben65]

Ok Guys, did a bit of research on the F111.... it is a fuel dumping manoeuvre, ignited by the engines' after -burner....a term they call Dump-and-burn, Zippo etc. Cool isnt it? Cheers.

[renold]

Ok Guys, did a bit of research on the F111.... it is a fuel dumping manoeuvre, ignited by the engines' after -burner....a term they call Dump-and-burn, Zippo etc. Cool isnt it? Cheers.

Many thanks to Reuben65 who spent time on reserach and share with us.

Would like to see more aerodynamic discussions and thinking on DH.