Air to Air refueling.Would you contemplate it?

[lasernigel]

Air to Air refueling.Valid in civilian aircraft or not?

Noticed this article (www.timesonline.co.uk/article/0,,2-1704606,00.html) in todays Times.From what I have come to understand(being a non pilot) air to air refueling takes a lot of practice to get right.I realise that his argument about fuel usage/weight is a valid point.But from a safety aspect would you like to try to find a tanker and hook up in turbulence?
Thought Air force one was crewed by military guys anyway.

[Lon More]

I'll have a pint of whatever the author was drinking please.

Not the safest manoeuvre. I had one trip on a tanker years ago (ANG KC97 -the one in the Dayton museum btw) everyone wearing a 'chute and considerable briefing beforehand.
One point not mentioned; aircraft departs with minimum fuel load, second aircraft, carrying loads of fuel departs. Highest fuel burn is during take-off so it's just been doubled.

Aircraft could refuel over the North Sea. Yeah, right. OK if there's just one, maybe. But get ten or so trying to do it at the same time in a very busy bit of airspace and ....

Bet the same guy will shortly prove bumble bees can't fly.

[Jerricho]

I wonder if they also have though of air-to-air toilet waste removal? And the booze :uhoh: ;)

But seriously, from my understanding of AAR is the optimum altitudes are around FL250ish. That would mean a great deal of climbing and descending around these "air gas stations" from optimum cruise levels, which could get very busy indeed. Throw weather/turbulence and FLEX tracks into the equation......what a mess.

[BEagle]

The planning of AAR, rendezvous between tanker and receiver, achievement of contact and transfer of fuel requires considerable training and practise. Military aircraft refuel in designated AARAs or ALTREVs and at heights which are not particularly suitable for optimum cruise for civil airliners. Whilst refuelling the aircraft do not comply with MNPS requirements; the modification of aircraft to receive fuel adds structural weight and the process of AAR is not conducive to passenger comfort.

Routine AAR cannot be carried out unless both aircraft are visual with eachother prior to contact; this may also require FLIR or similar systems at night.

The paper is UTTER nonsense; whilst it may be convenient for Air Force One not to have to land (due to security issues) for extended periods, AAR for modern, fuel efficient civil aircraft is simply not needed.

The argument concerning fuel usage is a total fallacy - don't forget about the fuel which the tanker would have to burn!

[Wizofoz]

I must say, I've often wondered if the idea of ATA fueling was abandoned to early in civil aviation. If the initiatives of the 1930s' had been continued, we might now be in a situation where the infrastructure/saftey/training issues had long been resolved.

I've also wondered how much more viable Concorde may have been had it had the unlimited range ATA provides.

I agree that, as it is such a fundimental change in the way civil aviation operates, it is unlikely to ever be implemented, but iti is never the less an interesting concept.

As to the extensive training required, during the Falklands conflict the Vulcan pilots who staged the quite incredible missions from UK bases had never ATA refueled until two days before the mission!

Amasing whet can be achieved with sufficient will.

[Capt H Peacock]

This has to be the most ridiculous suggestion I’ve heard in years.

- Military pilots train long and hard to achieve a qualification with regular practice.
- The thought of airliners bumping along over the GNAFA in pitch black, round CBs, and in moderate chop would fill me with horror.
- What happens if the probe breaks?
- What happens if it’s too turbulent to hook up?
- How will we cope when Big hog the tanker at Lambourne because there’s 10 minutes holding?

Time to check the medication methinks doctor.

[Art Field]

Wizofoz, As one of the Victor Air to Air Refueling instructors who taught the Vulcan crews prior to their Falkland sorties I'm not quite sure where your two day story came from. The facts were that the Vulcan crews had four receiver sorties and, with one notable exception who ended up in Rio with a broken probe, carried their Victor pilots on their operational trips. It is also worth pointing out that the Vulcan was the most pleasant of all RAF multis in the receiver role. I certainly do not wish to minimise the Vulcan crews achievements, merely to observe that, even with such a benign aircraft, skill and confidence (a vital element when you are hitting something attached to another aircraft very close to you) does not come easily with just two sorties.

[West Coast]

Even when completed by two well trained crews, the risks associated with AAR exceed those we would want of air carrier aircraft. Every now and then grief happens to trained aviators during the process. There the risk analysis falls in favor of continued AAR for mission accomplishment. In the civilian world I simply don't see the trade off. The risk is not worth the gain.

[Jerricho]

And........

Will you be paying by cash or charge? Would you like to buy a plane wash as well?


;)

[Immelmann]

From my experience (several atlantic crossings as AAR-receiver, instructorpilot) I do not see the civil aviation with the need for AAR. The training needed is based upon a military pilot carreer i.e. formation flying.
- So just from the basic training - not recommended.
- operational wise (airspace restriction etc) - not recommended
- economicaly from my point of view - not recommended.

Allover: what a strange idea!!
:suspect:

[BOAC]

Would you like to buy a plane wash as well of course if you ham it up you get a plane wash for free................ methinks Mr Green needs a holiday.

[Yellow Sun]

My background is as a large aircraft receiver and whilst I broadly agree with most of the foregoing comments I believe that "if",and it's a very big "if", there was a sound financial/environmental case for civil AAR then it would be made to happen. It would require new technology and systems (I really can't start to think what these might be) but if the business case was there, then it could/would become possible. However, having read the article in today's Times I can't really see that the case was made. Civil AAR is most unlikely to occur.

BTW Wizofoz


the Vulcan pilots who staged the quite incredible missions from UK bases

Not from the UK but Ascension Island. Although it is worth recalling that 101 Sqn flew UK-Australia non-stop with AAR in the '60s

YS

[BEagle]

A 101 Sqn VC10K also flew non-stop UK-Australia with AAR in Apr 1987. I believe the 15hr 53 min record still stands....

[Wizofoz]

Art Field and Yellow sun,

Thanks for the clarifications, was writting from pure memory (and I was 17 at the time!!)

All the points made have been valid and, as I said, the huge, fundemental change in civil operations would probabley make this a non starter BUT, if there were an overwhelming economic advantage, no doubt the problems would be overcome.

[John Farley]

Even though the only thing I ever had trouble keeping plugged in was a heavy two seat Harrier that did not really have enough push to deal with a Victor centre hose at high altitude I offer some comments.

Some people seem to be assuming that lots of civil flights could finish up doing AAR but that was not how I read the thrust of the article.

Some people are worried about not getting fuel. Why? Just another case for a diversion.

I think all of the present military need for skill, currency requirements and associated issues would never apply because a civil system would only be certificated if it was easy and safe – namely automatic. If I was a boffin I would sooner have to develop such a system than one that actually lands the aircraft when the crew can not see the runway because of fog. A FBW drogue that homed on a probe would not stretch modern robotics at all.

As a passenger I would be pleased not to have 20 hours fuel on board when any abnormality transpired during take-off.

I see modern airliner and cargo operations as a pure market driven commodity and so would not rule out any development (not just AAR) that might become possible in the future if it opened a new market or gave a competitive advantage in an existing one.

Pilots in general have been too quick to shout NO regarding many things in the past which have nevertheless happened very nicely thank you. In my view by doing this they weaken their case to be treated as thinking professionals. A more reasonable response that results in them being asked to the meetings is “Sounds a good idea but we will need to resolve a few issues first”

Finally, think about how any exhaust gases that we dump in the atmosphere below the tropopause get mixed and washed out by weather. The same stuff dumped in the stratosphere stays there. The pressure to cruise lower is going to come. That will change designs and operational procedures to put it mildly.

[SR71]

With the A345 and 777ER being able to link almost every major city pair in the globe, who needs it?

[John Farley]

SR71

I exect our posts crossed. In which case I'm sorry.

If they didn't I rest my case.

JF

[exvicar]

But surely if you cruise lower than your optimum FL, you burn more fuel hence more pollution! Surely the answer must be to ban all cars & air travel & bring back the sail boat. That would keep the raving greenies happy. Personally I would rather cruise at a lower level, not because of fuel burn, but due to the fact that I value my tessies.

[Art Field]

John Farley, your point re a FBW system is, as always, well made. The interesting fact is that AAR using the probe and drogue system as invented by Sir Alan Cobham has really not changed at all from its origin just after the second war. I wonder if a FBW system could cope with a bouncing drogue or come to that whether the passengers could cope with a FBW system chasing a bouncing drogue.

You may be able to dampen the receiver responses but damping the drogue ?. Nonetheless one would not wish to stand in the way of progress and I know there are many service pilots around the world who would welcome such an advance.

[BEagle]

A reasonable amount of progress has been made towards drogue stabilisation and autonomous AAR, particularly for UAV refuelling.

But for any airline application, the boom method would probably be simpler and would provide higher transfer rates.

A commercial airliner would need to take-off to make good a RV time (try telling that to ATC flow control!), climb to cruise level, descend to AAR level, find the tanker, achieve contact, take-on the required fuel load, then depart, climb back to cruise level and continue... If the transfer failed, the airliner would still need to make a safe landing somewhere; if the reason for requiring AAR is to increase ZFW and reduce fuel load, that'd mean arriving somewhere with several hundred pretty annoyed passengers.

And who would sell a ticket for a flight which was intending to depart with insufficient fuel to make its scheduled destination!

[John Farley]

Art

I had in mind a FBW droque with vanes that control it onto the probe as was suggested to Cobham by a bunch of students a couple of years ago. Cobham were well impressed but felt the military could cope as is and so there would be no return on the R&D

BEags

You are dead right about flow rates being higher with a boom of course. But I don't see why a tanker should have an ATC delay on take-off as it would not have to operate from a busy airport.

exvicar

The reason to fly lower (below the trop) is that pollution is a much less of an issue in the troposphere where mixing and washing occurs. Above the trop in the stratosphere pollutants get relatively trapped and build up much more.

I am not arguing in favour of AAR for airliners just trying to stop people being unreasonably dismissive by only listing disadvantages. There are a variety of advantages to the notion and only a properly balanced study will decide whether the idea should be actively studied or shelved pending XYZ..

JF

[BOAC]

Sounds a good idea but we will need to resolve a few issues first - you are dead right there, John! Having spent some significant time in my life topping up my meagre fuel supply from an airborne petrol tanker, I suspect 'the few issues' will be proven terminal for all but a limited few flights. I vote firmly with Beagle on this one.

Technically possible - without doubt
Within average pilot skills (with given augmentation) - without doubt

Commercially a dead duck. Incidentally Beagle's 'slot delays' were for the receivers.

What does the tanker do? Racetrack or straight line? If the former, there would be multiple loops of the track to take on the quantities we are talking about, with enormous wastage of fuel going nowhere. When No1 in the plan gets delayed by late bags or ATC slot, No2 presumably 'slots in' when it arrives, making No 1 wait while No 2 tanks when No 1 arrives. Assuming gargantuan efficiency in planning, No 3 will then be waiting for his 'scheduled' tank when No 1 gets his. Do we go on? If a 'straight line' tank, poor old No1 cannot catch up with the tanker which has gone off along the route with No2. How much 'redundancy' do you build in for such 'misfires' of the plan? More fuel burnt by the tankers.

Now airspace - for race-track tanking, with one fueling and one waiting, we block off half of the North Sea. I actually do not think there is airspace for it. Having been rolled out in front of a tanker at least once, I can see some of our brethren finding a few difficulties too! :D

just trying to stop people being unreasonably dismissive by only listing disadvantages - I'm afraid you'll have to count me in that camp, John, except I do not think it 'unreasonable'. I am struggling to find any 'advantages'. I place this plan in the Short-Mayo group - a good idea, will work for special flights, but will not work in practice. Have you seen the 1700 scheduled 'push' out of LGW or LHR? Alternatively, if we limit it to a selected few longhaul flights, is it worth the effort?

Anyway - who is going to give Ryanair any fuel without a signature....:D

[John Farley]

Chaps

I understand why practical aviators with AAR and airline experience see so many problems.

However although I consider myself a (former) practical aviator I do not feel I have the intellectual hoprsepower to say 'rubbish' or simply 'no' in the face of the following:

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.

Of course I WOULD like to ask them a bunch of stuff. In the event they have the right answers I would then say 'Cor!'

JF

[Flight Detent]

Hi guys,

Just to throw a cat among the pidgeons, there are B737NGs currently flying around with both an AAR and Fuel Jettison capability.

You guessed it, they are military modified airplanes flown by military pilots, without paying pax aboard!

Taking into account the very low fuel flow of an 737 at MRC or LRC speeds, these things should be able to stay inflight for a very long time!

Just thought I'd mention it!

Cheers, FD

:ooh:

[BEagle]

One wonders whether the 'Rolls Royce and Airbus' representatives were people with an interest in trying to find some way of achieving 'third party revenue' with the Rental Air Force's proposed AirTanker A330 MRTT a/c when they are not refuelling the remaining handful of serviceable RAF 'fast' jets...??

I still do not understand what the basic reasoning behind such an expensive, fuel guzzling idea is supposed to be......

Regarding lower cruise levels, perhaps the Boeing Pelican 'ground effect' design is the ultimate? They claim that it could transport 750 tons over 10,000 nm when cruising in ground effect, but only 6,500 nm when cruising out of ground effect.

[Gainesy]

Off topic for a sec, personal bee in bonnet, sorry chaps.

As a passenger I would be pleased not to have 20 hours fuel on board when any abnormality transpired during take-off.

As a pax I'd be more comfortable if there were not a half ton or so of duty free inflammable spirits in glass bottles in the overhead lockers. Buying DF at destination should be adopted.

[Seat1APlease]

Whilst it might be technically possible I don't think it would be cheaper than a tech stop, and wouldn't reduce airfares.

The one item missing from the debate is the view of Joe Passenger.

If you talk to a passenger travelling economy after a flight from SIN-LHR or LAX-SYD I don't think the prospect of another 6 or 7 hours sitting in the same seat would have much appeal.

Add to that the whole debate on DVT and I think it is a non starter. Some airlines such as SQ are thinking in terms of an upgraded economy product on their ER aircraft but I cant see the majors taking half the seats out to allow a promenade deck.

It might work for an all business class point to point service from say LHR to SYD with a few extras such as on request oxygen/water vapour masks, and space to walk/shower etc but I have my doubts.

[Wizofoz]

Seat A1,

As someone who does the UK-Aus trip, let me tell you that the simple fact is you are spending 20 hrs in a seat regardless. The only difference is- are you going through the stress, inconvienience and possibly catastrophic disruption (Tech problems, missed connections, booking foul ups etc. etc.) of getting out of that seat half way, sitting around a terminal for a few hours, then getting back into that seat for the completion of a 32 hr point-to-point trip.

Sit down in London, get up in Sydney? Yes Please!!

[SR71]

Hey John,

If they didn't I rest my case.


I've done enough time in R&D to know "Never say "Never"!"

Economics versus Environmental Science?

The balance of power between the two may shift somewhat in the future but I suggest not at $60/barrel and, even then, only when the USA says it should.

Unfortunately.

I'm not a meteorologist, but even at FL370 I come across some pretty significant winds over NW Europe. No doubt aviators up in the 400's do too?

That suggests to me there is some signifcant atmospheric mixing going on even up there... Maybe only in a horizontal sense though?

You're saying there isn't much vertical mixing (How the hell is Steve Fosset going to get to 100,000ft in a glider then?) and the particulate matter can't break through the tropopause?

Doesn't that generalisation really depend on what latitude you're at?

Ignorantly.

:)

[Jetstream Rider]

Wouldn't the environmentalists complain about stuff in the oceans if we flew lower and it got washed out?

Its interesting seeing this discussion develop. I must admit, I saw the article and thought it must be April Fools day.

I would love to have a go at tanking and it is obviously possible, but on a large scale as suggested?

The guys at Cranfield et al command a huge amount of my respect, but this does remind me of the Cranfield boffs who said we could fly LHR-SYD via space by 2000.

[Piltdown Man]

So we take off with bugger all fuel. Then ask for radar vectors so we are in exactly the same piece if air as somebody else (after having turned the transponders to one click less than TA). Then fly MANUALLY (how do you do that?) to make a lump of scaffold pole bumb into an oversize shuttlecock, fill up the plane with probably the most expensive juice known to man and then go to where we could have probably gone in the first place, had we put enough fuel in . And the CAA (amongst others) will say...

I think not!

[Hanse Cronje]

If you have not put your probe in a basket then you have not lived.....

[Art Field]

Well then, I've lived 1129 times and I don't count the ones I've sat through. All in 4 engine beasts too. Just felt like blowing a trumpet for once, so there.

[Wizofoz]

Then fly MANUALLY (how do you do that?) to make a lump of scaffold pole bumb into an oversize shuttlecock,


the same way military pilots have been doing it since the 1950s'!?!

[LowObservable]

Without looking at the original data, my guess would be that the people who came up with this idea are right, but also wrong.

They are right that the longer you fly, the more fuel per mile you burn, other things being equal - because on an 8000 mile sector you have to carry the last pound of fuel that you burn for 8000 miles. Adam Brown of Airbus used to twit Boeing with the fact that Condit once claimed that ultra-long nonstops saved fuel.

On the other hand, I wonder if they have factored the fuel used by the tanker into the equation, let alone taken account of ascent/descent, allowances for missed refuelings, multiple attempts and so on. At that point, you might save more fuel by making a fuel stop.

[John Farley]

Some may find enjoyment in shooting messengers but such a practice (however inconveniently) does not of itself invalidate the message. I didn’t invent the physical laws that define the way our atmos behaves so give me a break. In a similar vein the fact that boffins said we could do something by a certain date is not at all the same as saying we would.

SR71 On a more practical point I understand Steve Fossett is looking to use a standing wave which while not occurring too often as high as 100K does happen much more frequently than thermal mixing in the absence of a lapse rate! You were dead right that what we feel is going on (often as CAT) is thanks to the marked horizontal sheers caused by jet stream activity. The height of the tropopause is a most variable feast and I believe has been detected as low as 25 and as high as 55 even though we tend to think of it in ISA terms as about 35. In the end the troposphere and the stratosphere are just bands of atmos inside which certain observed conditions apply that happen to keep them from mixing into one single layer.

Chaps - purely by chance I had to attend functions at the SBAC and Dti today in respect of engineering educational matters. Imagine my surprise (or not) when I was grabbed by senior wheels and had my ear filled to the brim not with the newspaper article (that has clearly got to a few PPRuNers) but with the technical paper behind the article. But for goodness sake don’t read it as I hate to see grown men loose confidence in themselves.

I am so f-ing knackered after today that I can’t believe I am taking this thread seriously again.

[BEagle]

JF:
"But for goodness sake don’t read it as I hate to see grown men lose confidence in themselves."

Which 'grown men'?

OK - I'll be blunt. From a country which produced the sort of brains which came up with Concorde and Harrier, this proposal for airline AAR is, quite honestly, barking mad boffin stuff.

An airliner is supposed to fly 3000 miles between AAR sessions, is it, green boffins? Call that 6 hours at a still-air TAS of 500 KTAS. At 5 tonne per hour (typically), that's 30 tonne of fuel. Receiving it at even 2 tonne per minute (pretty optimistic) would take 15 minutes in contact; at tanking speeds that's a still air distance of well over 100 nm. So our airliner takes off, climbs to opt cruise, descends into a 100nm+ AARA, RVs with a tanker, takes on 30 tonne of fuel, then climbs back to opt cruise......and does that every 5 hours on its way to Australia? That'd mean a refuelling bracket in the North Sea, another over Siberia and a final one over the Phillipines. Personally I wouldn't by a ticket for a flight which might dump me in the middle of nowhere after a failed AAR RV - but perhaps the green boffins know better?

[John Farley]

BEags

Thanks for that. As ever you have put your finger on the crux of the matter. Such a process will never be certificated unless it is shown to be safe and reliable – as I remarked in my first post.

But in my view all the rest of the objections offered in this thread are invalid knee jerk reactions unworthy of professionals.

We are all entitled to our own best guess as to whether the necessary reliability and safety could be developed and proven (given the costs against and the ‘green’ pressures for). I would guess not, but that is not the same thing as just shouting “Rubbish!”

JF

[SR71]

I don't understand...

In this business you have a 735 which will operate a 1000nm sector and a A345/777ER which will operate a 9000+nm sector. There will come a day soon when 10000+nm is possible. No doubt already is in low density configurations.

There are products which offer you ranges in between the above.

Lets assume that the product you want to operate over the range you need has the right capacity.

Conclusion: AAR not required.

So the question only arises when you want to operate a low density long range route for which no product exists. (I take the view that the A380 has been sized correctly to deal with high density longest range routes. Pretty silly if it wasn't!)

In the long run I cannot see how it is not better to design your aircraft to meet the operating criteria rather than endeavour to get a sub-optimal product to do the job via AAR? This is proposed as a short term fix which will, bearing in mind the objections mentioned already, will require significant investment for what ultimate gain?

Taking a long term view, I just don't see the point of AAR unless the big A and B are going to stop building the aircraft that their customers need.

I can quite believe there is good science behind it but strategically?

:confused:

[John Farley]

SR71.

I see what you are getting at. The case FOR is as simple as this:

The sums for a cruising aeroplane show a lower fuel burn at a lighter weight.

The fuel used climbing from take-off to the cruise is very sensitive to takeoff weight.

Because of this a technical case has been made that if AAR was used – even allowing for the tanker fuel – then less fuel per pax would be needed on long routes. Toss in the way aircraft could be made lighter if they never had to be capable of containing as much fuel in the first place and very soon a virtual circle develops.

BUT this analysis does not allow for two things.

1 BEag’s safety issue

2 Market resistance to the investment needed (scrap existing types early, develop new versions, develop auto tanking) for a limited advantage.

Without wishing to flog a dead horse we have just about cracked the provision of types that will go half way round the world non stop. So what next? One answer has been for people to say a step change in fuel burn could be achieved using AAR.

JF

[Art Field]

Further to Beags points on safety and complexity, as he and I have experienced many times, the problems resulting from trying to get two aircraft in the same place, at the same height, and going in the same direction are not doubled but (and I use this logic with caution after the recent medical case) probably four times i.e. squared. Again not insurmountable but odds that I suspect the airline industries bean counters would need some convincing to accept.

The use of AAR in the military for deployment means that, along with other advantages, awkward diplomatic questions can be avoided, the notorious servicability of fast jets can be moved on and crew duty restrictions overcome and so the odds are accepted. These problems are nothing like so significant in civil aviation. Although advances in technology may be able to reduce the odds I still feel the "green" gain would be well below the theoretic figure.

[BEagle]

Having known Art Field since I was briefly one of his 'Dougie Bs*', what he doesn't know about the problems of AAR organisation, execution and safety simply isn't worth a dime, as the Americans might say...

So perhaps the Green Boffins might care to listen to the voice of experience rather than trying to re-invent a square wheel? Fair enought to 'think outside the box' as they might say - but not if it's total bolloc....err, nonsense!







* Dougie Bs. When Art Field came from his ancient crescent-winged device to the majestic Vickers FunBus, he was astonished to learn that VC10K co-piglets were allowed to operate as 1st pilots straight out of the OCU, unlike their erstwhile V-force predecessors. He didn't seem to hold with this notion, hence his co-pilots didn't have operating legs. Like Douglas Bader. Hence we termed them 'Dougie Bs'! ;)

[Art Field]

Thanks Beags for the commercial, albeit it with a gentle sting.

Further thoughts relevant to large aircraft refueling. Airframe fatigue will be increased with particular stress on the tail area which, dependant on its design, will receive a degree of engine and airframe buffet from the tanker. Engine life will be reduced as there will be significant RPM changes during the refuel causing temperature stress (engine designers expect little RPM variation in cruise, I was told by a man from RR that more than 2% change constituted a stress cycle).

Fuel consumption increases by at least 40% during the refuel (fighters by 100%). If a fixed probe is used then a further fuel penalty is incured and the wind noise round the probe may keep the pilots awake. I would expect some form of retractable probe to be fitted but it could fail. Not of course a problem if the boom method is used. Either method carries a very small risk of airframe damage from human or equipment failure. The not inconsiderable increase in noise from the tankers engines will not go down well with the nervous punter.These are some of the factors which must be considered in balancing up the viability of the proposal.

[BOAC]

the wind noise round the probe may keep the pilots awake :D :D

Like it! Can I have one?:D

[Saintsman]

fill up the plane with probably the most expensive juice known to man

Slightly off topic but if aircraft flew on printer ink, tanking would be the norm!

[Been Accounting]

At last we get close to the most important point... how much will the fuel cost at the pump?

Wasn't there an recent article about AAR in AWST (or was it Flight or JDW..) that quoted 20USD/USg for fuel supplied by tanker aircraft.

Which airline would pay that price?

[Footless Halls]

I never thought I'd see the day when I might spot something which such eminent gents (& ladies?) as yourselves might have missed, but I think the missing word here is TAX.

if you do a search on The Guardian's website, and perhaps of other treehuggers' habitats, you will see apparently serious proposals that aircraft fuel should be taxed 'for Africa' and perhaps also for other, on the face of it, laudable reasons.

Germany & France are supposed to be very keen on this.

I think someone may have spotted that in-flight refuelling, if adopted by civil aviation, would render this putative EU-wide tax hike unsustainable.

I DO hope so!

[PAXboy]

Pax point of view: So, let me get this straight ... You want to offer me the chance to have the flight change altitude and slow down? During the next 30 or 40 minutes(?), we might well be bumped and jostled around in a slipstream that we cannot get away from? Also, we will hear an extra loud noise from another aircraft that is just nearby?

What about that bit about not allowing aircraft to get too close to each other? What if the weather conditions in the area change too rapidly? If, during this time, the turbulence gets bad? Normally, I understand, flight crew do their uttermost to avoid turbulence and will change levels to get away from it?

Lastly, on a long flight, we shall have to repeat this? And, if all of this doesn't work out, we will land at whatever place can take us and use up as much time as we would have in the first place with a scheduled stop? But now it will be unplanned and my arrival time is gone to heck and I have to use the expensive sat-air phone to call my family/biz contacts with a change of plan!

OK, let's hand that over to the marketing boys and see if they can sell it ...:rolleyes:

--------------------
"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.