Civilian Air-to-Air Refuelling

I read in the paper this morning (The Times [London] - 23 July 2005 - page 29) that the Royal Aeronautical Society's Greener Design Group (RAES) have put forward the notion of air-to-air refuelling for civilian airliners. They cite the reason that fuel will be saved as a significant proportion of fuel is used, on long haul flights, either getting up in the air or carrying more fuel that is used for the distance. The proposal was to have fleets of tanker aircraft (no doubt privately owned) operating from military bases (why?) that would go up and refuel aircaft during flight. It also suggests that straight after takeoff would be a good time for an inflight refuelling as it allows for a lighter takeoff weight and will therefore reduce the amount of thrust needed and hence the amount of fuel used. This includes the fuel used by the tanker as well, apparently, which itself can fuel around 4 airliners.

The optimum distance would be around 3000 miles apparently. It therefore suggests that should this be taken up that we will see the end of larger aircraft and more efficient medium-range aircraft would see a surge especially those designed for a range of around 3000 miles. Finally it also adds that it would be safer for passengers as the extra hops involve more takeoffs and landings, which I'm sure most of you realise is the most dangerous (statistically) part of the flight.

If anyone looks up this article can they confirm that it appears that the aircraft in the diagram are in the wrong order with the refuelling drogue going forward rather than back????

I ask you....would you be happy with the cheaper, more efficient and perfectly safe in-flight refuelling or do you think that kind of dangerous stuff ought to be left with the military?



EDIT: The below:

P.S. I'm sure I'm not alone in having considered this since I first discovered about air-to-air refuelling

[edit on 23/7/05 by Infidellic]

Originally posted by Infidellic
IP.S. I'm sure I'm not alone in having considered this since I first discovered about air-to-air refuelling

[edit on 23/7/05 by Infidellic]

You certainly aren't, look below at what Imperial Airways (the British Airways of their day) were doing in the 1930's;

I don't think that it would be cost effective, you would have the expense of the airliner as well as that of the tanker. The cost of operating the tanker would more than out weigh the money saved by conserving the fuel. You could accomplish the same thing by relaxing the FAA regulations on divert fuel.

Hmmm I think it would be a bad concept. For one long haul airlines already are about at the limit of endurance for crew and passangers. SIA is already having a second crew planned for some of its 777-200LR's cause they can stay in the air for a really long period of time. Same for the A340-500. SO if the plane already has a range of 10000+ miles would it be to your benifit to go further. Yes a ligher plane is easier to take off, but the tanker is just as heavy and has to loiter waiting to refuel etc.

If you did not know the A340 and the 777 and 747 have an overhead crew rest area that most people never see with bunks etc. Its a bit cramped but a nice quiet place to rest for the crew on long hauls. The A380 will have a similar arrangement

As long as someone develops airship capable to reach speeds at which civilian airliner can refuel there will be nothing from this I fear. The tankers are too expensive to operate and all or at least majority planes would need to be equipped by inflight refueling devices.

Bad Idea. Do you know how difficult it is to keep two airplanes that close to each other for as long as it takes to put fuel onboard? And the potential for an accident? Very Bad Idea.

Originally posted by JIMC5499
I don't think that it would be cost effective, you would have the expense of the airliner as well as that of the tanker. The cost of operating the tanker would more than out weigh the money saved by conserving the fuel. You could accomplish the same thing by relaxing the FAA regulations on divert fuel.

It said in the article that they examined this and it would work out cheaper overall apparently. I take everyones safety fears into account though. Do you think that technological advances would enable the aircraft to stay together far more safely? I.e. there being a system where the aircraft would 'talk' to each other and fly exact distances from each other for extended periods.

The article can be found here

The article reads (courtesty of The Times Online):

PASSENGER jets could be refuelled in mid-air under proposals by the aviation industry to save fuel and reduce the environmental damage from flights.

Giant tanker aircraft would fill the tanks of up to four airliners in a single trip, reducing the total fuel burnt by about a fifth even after taking into account the fuel used by the tankers.

Aircrafts on long-haul trips, such as from London to Sydney, would no longer have to land to refuel. It would be possible to fly non-stop halfway around the world with three or four air-to-air refuellings. The risk of jets colliding would be virtually eliminated by a satellite positioning system that would allow the pilot of the tanker to control both aircraft during the refuelling. Existing technology is already extremely safe and is used to refuel Airforce One, the US President ’s Boeing 747.

The proposal has been put forward in a report by the Royal Aeronautical Society’s Greener by Design group. The group includes representatives from the Department for Transport, Airbus, Rolls-Royce and Cranfield University.

The report concludes: “The potential benefits of air-to-air refuelling for long-haul flights are sufficient to justify a rigorous assessment of it from an environmental, logistical and economic standpoint.”

John Green, the group’s senior scientific adviser, said that existing long-range aircraft were an inefficient shape because they needed large fuel tanks and big engines to propel the extra weight.

He said that fuel was so heavy that a third of what was used on long flights was burnt simply in carrying enough fuel to remain airborne for up to 18 hours. Airliners also waste several tonnes of fuel on take-off because of the enormous thrust needed to lift so much weight. Fuel accounts for almost half of the 395 tonnes that a British Airways 747 weighs when taking off from Heathrow bound for Singapore.

Mr Green said that aircraft could in future take off from Heathrow with only a few tonnes of fuel and then rendezvous over the Irish Sea with a tanker.

In terms of fuel efficiency, the optimum distance between refuellings would be 3,000 miles. Mr Green acknowledged that air-to-air refuelling would require major investment in a new fleet of tanker aircraft. But he said that little extra ground infrastructure would be needed because the tankers could use existing military airbases.

Long-range aircraft would be phased out and replaced by highly efficient medium-range jets designed to carry only enough fuel for 3,000 miles.

The Greener by Design group has previously proposed that aircraft should save fuel by stopping more frequently to fill up on long journeys. However, this idea was dismissed by airlines because trips would take longer, increasing the need to have relief crew and deterring some passengers.

Increasing the number of “hops” on a long trip would also increase the risk of a crash because take-off and landing are the most dangerous phases of a flight. Mr Green dismissed concerns that air-to-air refuelling would pose an extra risk to passengers. “If it’s good enough for the US President then it ought to be good enough for us,” he said.

Sure you could make a system like that, but how do you account for wake turbulence, and just turbulence in general? It takes a long time for military pilots to become proficient in air to air refueling, and the thought of doing it with 400+ people on the plane is seriously scary.