Virgin Atlantic towing a/c to the hold.
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<<On the down side there would be a little more work for GND control. If you had a problem on start, getting back to the bay would be an issue. Weighing the occasional probleem against the savings still makes this a good idea.>>
With the greatest respect, some people on here really want to spend a couple of hours in the Tower at Heathrow or similar airport from where they might just get a different view. Slow towing aircraft can provide real headaches and there is no doubt that, overall, things would slow down. I'm sure Gonzo would confirm all this.
With the greatest respect, some people on here really want to spend a couple of hours in the Tower at Heathrow or similar airport from where they might just get a different view. Slow towing aircraft can provide real headaches and there is no doubt that, overall, things would slow down. I'm sure Gonzo would confirm all this.
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Which do you think has more of an impact - burning oil to produce electricity to warm up power lines, to charge batteries to move a truck to push an aeroplane.... with all the attendant losses and inefficiencies all the way down the chain..
Or just burn the oil in the plane/car in the first place?
Or just burn the oil in the plane/car in the first place?
Now are you prepared to backup your false statement with science, or are you content with accepting that you are just wrong?
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Litres and Litres
Heathrow Director.
Having operated in and out of Heathrow for many years I appreciate what the extra work load may mean. However for some reason the media has singled out aviation as the worst transportation polluter. Having just watched the BBC doc "Should we give up flying ?" it can be safely said that we as an industry must look for improvements, whatever the logistical implications.
Probably because to examine their own driving habits would be too difficult.
That said, the nose wheel tugs where meant to be "high speed' tugs. They are at least capable of sufficient speeds and when holding on the taxiway is expected they could be used. Their speeds could also be used to meter traffic in the sense that once all the traffic is moving it does not need to be doing 20+ knots to keep the departure flow rate the same.
As for better maintained, a badly maintained tug will still pollute far less than 4 Trents. Oh and you could service the tug too !!
For us long haul guys it means having a little extra fuel en-route on the days we would have cut into contingency before we even get off the ground.
We are talking about the savings of millions of litres per day industry wide. Surely we can sort soomething out.
Having operated in and out of Heathrow for many years I appreciate what the extra work load may mean. However for some reason the media has singled out aviation as the worst transportation polluter. Having just watched the BBC doc "Should we give up flying ?" it can be safely said that we as an industry must look for improvements, whatever the logistical implications.
Probably because to examine their own driving habits would be too difficult.
That said, the nose wheel tugs where meant to be "high speed' tugs. They are at least capable of sufficient speeds and when holding on the taxiway is expected they could be used. Their speeds could also be used to meter traffic in the sense that once all the traffic is moving it does not need to be doing 20+ knots to keep the departure flow rate the same.
As for better maintained, a badly maintained tug will still pollute far less than 4 Trents. Oh and you could service the tug too !!
For us long haul guys it means having a little extra fuel en-route on the days we would have cut into contingency before we even get off the ground.
We are talking about the savings of millions of litres per day industry wide. Surely we can sort soomething out.
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This could be a good plan if it is organised properly.....however there are lots of improvements that could be done around the airport to help the pollution/green issue; Many of the stands at LHR the fixed ground power does not work...check out the lovely new stands for the 380 (301-307) none of the power works on these stands and has been like that for weeks, the jettys are regularly failing, meaning buses for the passengers etc.....now a 747 APU running for a 3 hour t/round......towing to the runway would be good, but lets sort the basics out first....(cost theBAA money so they wont bother)
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Despite the cynicism of some - and the flat-earther-stylee climate-change denial of others! - this issue is one that has to be tackled, and someone has to be first to do it. There is no denying that any airline that acquires a mantle of environmental awareness will have an advantage in a marketplace that is sensitive to such matters, however, and Branson is a past master of exploiting such things.
The tug-to-the-runway approach is a coarse first step in a process which will eventually see aircraft making their way to the runway with their main engines shut down. Whether that's by the 'shopping trolly' system mentioned earlier, or auxiliary electric axle motors on board, or some other system is irrelevent as yet - the fact is that the experiment and development phases must begin somewhere. I'm sure most of us can see many of the disadvantages in using old, dirty, and scarce tugs to drag aircraft to somewhere near the pre-departure hold, but this is surely to establish simply how much fuel can be saved and what problems actually transpire, as opposed to what might be anticipated. From the data and experiences learned, decisions can be made as to what the next step should be.
The tug-to-the-runway approach is a coarse first step in a process which will eventually see aircraft making their way to the runway with their main engines shut down. Whether that's by the 'shopping trolly' system mentioned earlier, or auxiliary electric axle motors on board, or some other system is irrelevent as yet - the fact is that the experiment and development phases must begin somewhere. I'm sure most of us can see many of the disadvantages in using old, dirty, and scarce tugs to drag aircraft to somewhere near the pre-departure hold, but this is surely to establish simply how much fuel can be saved and what problems actually transpire, as opposed to what might be anticipated. From the data and experiences learned, decisions can be made as to what the next step should be.
Simple, socially responsible, eco friendly solution .... get a whole lot of young lads with ASBO's into a chain gang and have them lug the aircraft around the field!
Unhappy ASBO chaps, happy hippies ...
win/win
JAS
Unhappy ASBO chaps, happy hippies ...
win/win
JAS
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what about an underground cable, like the cable cars in San Francisco? The aircraft could latch on to the continuously moving cable and detatch at the appropriate point. Just a far fetched thought.
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It would work
"Slow towing aircraft can provide real headaches and there is no doubt that, overall, things would slow down."
If all aircraft were towed, the departures would still be same as now. It would just take a little longer to get there.
If 3/min go to the hold at 20 mph under their own steam, or at 10mph by tractor, they'll still be released at the same rate.
It would work.
However I'm sceptical of this whole global warming thing. 30 years ago we were going to freeze. Its a natural cycle. The Leftie Greenies need some way to have a dig at the west and of course the "great Satan"!!!
Anyone seen C4's The Great Global Warming Swindle"? see http://video.google.com/videoplay?do...31355859226455
Yes it has an agenda as well but it gave me food for thought esp the ex Greenpeace founder!
Can anyone get the stats for the amount of motor fuel used in ,say, the UK vs the amount of aviation fuel?
If all aircraft were towed, the departures would still be same as now. It would just take a little longer to get there.
If 3/min go to the hold at 20 mph under their own steam, or at 10mph by tractor, they'll still be released at the same rate.
It would work.
However I'm sceptical of this whole global warming thing. 30 years ago we were going to freeze. Its a natural cycle. The Leftie Greenies need some way to have a dig at the west and of course the "great Satan"!!!
Anyone seen C4's The Great Global Warming Swindle"? see http://video.google.com/videoplay?do...31355859226455
Yes it has an agenda as well but it gave me food for thought esp the ex Greenpeace founder!
Can anyone get the stats for the amount of motor fuel used in ,say, the UK vs the amount of aviation fuel?
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All done before !
Twenty years back Dan-Air (remember them?) started taxing the B727 to the hold with the #2 engine shut down, it was then started just before take off as a fuel saving measure.
The number of # 2 engine failures dramaticly increased mostly due to the engine thermal stress that resulted when a cold engine was set to take off power.
All this nonsence will stop when the first few big fan's go bang!.
The number of # 2 engine failures dramaticly increased mostly due to the engine thermal stress that resulted when a cold engine was set to take off power.
All this nonsence will stop when the first few big fan's go bang!.
ex-Tanker
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Wheel Motors - Delta - Virgin
Thanks ETOPS for the links.
I am not convinced that the nosewheel is the best location for a wheel drive -such a drive should be near the CG to avoid slippage in wet / poor conditions.
I imagine that the complexity of the Main Wheel brake system (and the relative simplicity of the nosewheel) is what has led to this configuration.
Anyway, as long as the system is being developed, now surely would be the time for Virgin to assess it?
FC.
I am not convinced that the nosewheel is the best location for a wheel drive -such a drive should be near the CG to avoid slippage in wet / poor conditions.
I imagine that the complexity of the Main Wheel brake system (and the relative simplicity of the nosewheel) is what has led to this configuration.
Anyway, as long as the system is being developed, now surely would be the time for Virgin to assess it?
FC.
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Read the papers, people. Whether it's misguided or not, aviation is in the cross-hairs at the moment and has to be seen to be at least thinking about doing something.
Anyone who's sat in the evening departure queue at Kennedy in the last year or two cannot but have thought about how much juice is being spewed into the atmosphere. Some posters on this thread have called for independent evidence - well, that's what a trial is for. It may well be that, taking into account the cost of buying and running all the extra tugs needed, the impact on arriving a/c of having to perhaps taxy around departing a/c under tow, etc. might stop it in its tracks. Then again, it might be that a tonne or two can be saved per 747, per departure on average and over the life of the a/c, that's a saving that any rational carrier couldn't sneeze at. Management is also under a duty to shareholders to constantly look at ways of cutting costs.
Starting grids? Little different from de-icing grids at some airports or the little circular holding bays that some airports used to have near the runway ends. Kennedy already has engine starting points off the taxiways - so not a totally alien concept - so it's just a matter of moving these out on the field (ok, a bit of construction will be involved).
Engine probs due to cold starts? OK, so f'rinstance at Kennedy, rather than have all 4, or both, running for an hour or more in the queue, start them up (or the ones which weren't started straight after push-back) out on the field with 20 or 30 mins to go (I don't think anyone's suggesting going straight from the start point onto the departure runway).
Aviation needs to be seen to be doing something. It is in the interests of all those in the industry to look for ways to cut emissions (and costs). Being seen to be pro-active is better than being seen as having to be dragged along. This issue will not go away.
Anyone who's sat in the evening departure queue at Kennedy in the last year or two cannot but have thought about how much juice is being spewed into the atmosphere. Some posters on this thread have called for independent evidence - well, that's what a trial is for. It may well be that, taking into account the cost of buying and running all the extra tugs needed, the impact on arriving a/c of having to perhaps taxy around departing a/c under tow, etc. might stop it in its tracks. Then again, it might be that a tonne or two can be saved per 747, per departure on average and over the life of the a/c, that's a saving that any rational carrier couldn't sneeze at. Management is also under a duty to shareholders to constantly look at ways of cutting costs.
Starting grids? Little different from de-icing grids at some airports or the little circular holding bays that some airports used to have near the runway ends. Kennedy already has engine starting points off the taxiways - so not a totally alien concept - so it's just a matter of moving these out on the field (ok, a bit of construction will be involved).
Engine probs due to cold starts? OK, so f'rinstance at Kennedy, rather than have all 4, or both, running for an hour or more in the queue, start them up (or the ones which weren't started straight after push-back) out on the field with 20 or 30 mins to go (I don't think anyone's suggesting going straight from the start point onto the departure runway).
Aviation needs to be seen to be doing something. It is in the interests of all those in the industry to look for ways to cut emissions (and costs). Being seen to be pro-active is better than being seen as having to be dragged along. This issue will not go away.
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Logic
Brain Fade :
There is certainly an issue with extra manufacturing impact of more tugs. However I think that once an airline has obtained the extra tugs needed they will eventually re-coup that impact with the savings. We are talking about a huge amount of fuel globally. Additionally once airlines get organised they should be able to do this with less increase in tugs than is suggested, as a tug's utilization rate is not that high (ie they sit for some time after each aircraft they push/pull in.) Obviously depends on airport and airline and airline flight frequency. Perhaps pooling the tugs would be a way to go.
I think initially it would work well to tow out but not so for towing in (unless waiting for a gate and then the tug should be sent out) We burn 1.5 tons parked on a taxiway with one shut down, while waiting aprox 40 mins for a gate.
As far as engine wear goes, might not need 20 mins as sometimes our taxi times are very short and we launch in under 10 mins from last engine start.
Like the cable idea !!
Cheers
FG
There is certainly an issue with extra manufacturing impact of more tugs. However I think that once an airline has obtained the extra tugs needed they will eventually re-coup that impact with the savings. We are talking about a huge amount of fuel globally. Additionally once airlines get organised they should be able to do this with less increase in tugs than is suggested, as a tug's utilization rate is not that high (ie they sit for some time after each aircraft they push/pull in.) Obviously depends on airport and airline and airline flight frequency. Perhaps pooling the tugs would be a way to go.
I think initially it would work well to tow out but not so for towing in (unless waiting for a gate and then the tug should be sent out) We burn 1.5 tons parked on a taxiway with one shut down, while waiting aprox 40 mins for a gate.
As far as engine wear goes, might not need 20 mins as sometimes our taxi times are very short and we launch in under 10 mins from last engine start.
Like the cable idea !!
Cheers
FG
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It's all about a series of uphill runways, running in all directions.
Planes stop quicker when landing, then they can free-wheel from the top of the runway downhill to the terminal, which would be located half way down the taxiway that's parallel to the runway. Then, when departing, they can freewheel down the rest of the hill to the bottom of the runway.
OK, so they have to take off uphill, but seeing as they're going up anyway...
Planes stop quicker when landing, then they can free-wheel from the top of the runway downhill to the terminal, which would be located half way down the taxiway that's parallel to the runway. Then, when departing, they can freewheel down the rest of the hill to the bottom of the runway.
OK, so they have to take off uphill, but seeing as they're going up anyway...
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Even if you assume that a tug has only 1/10th of the fuel efficiency of an average SUV there is no way it could burn a couple hundred kgs for 3-5kms of push to the runway.
We use single-engine-taxi in and out whenever there is a longer taxi time and there is no evidence of increased engine stress if the required warm-up times before departure are adhered to.
Towing to the runway and no-diesel ground power won't save the planet single-handedly but it sure makes sense to cut emissions and noise wherever possible.
It would, of course, save a lot more if we just got startup and pushback clearances in time to avoid endless holdings before take-off. It is pretty inconceivable that we're unable to predict at least a little better when to release A/C from the gate in order to have not more than 2-3 waiting at the holding point.
It would save even more if we'd invented a better way of sequencing A/C so as not to have dozens of them in holdings (left of the channel) or flying useless mileage along huge waypoint-based traffic patterns (right of the channel) at inefficient speeds and altitudes.
AEA claims that we could save app. 10% of all fuel burned in aviation by just having a single Eurocontrol ATC and that is probably not far off the mark.
All these better potential savings are no excuse for not doing the small stuff and sometimes taking public tranport ourselves
We use single-engine-taxi in and out whenever there is a longer taxi time and there is no evidence of increased engine stress if the required warm-up times before departure are adhered to.
Towing to the runway and no-diesel ground power won't save the planet single-handedly but it sure makes sense to cut emissions and noise wherever possible.
It would, of course, save a lot more if we just got startup and pushback clearances in time to avoid endless holdings before take-off. It is pretty inconceivable that we're unable to predict at least a little better when to release A/C from the gate in order to have not more than 2-3 waiting at the holding point.
It would save even more if we'd invented a better way of sequencing A/C so as not to have dozens of them in holdings (left of the channel) or flying useless mileage along huge waypoint-based traffic patterns (right of the channel) at inefficient speeds and altitudes.
AEA claims that we could save app. 10% of all fuel burned in aviation by just having a single Eurocontrol ATC and that is probably not far off the mark.
All these better potential savings are no excuse for not doing the small stuff and sometimes taking public tranport ourselves