Heathrow Holding....
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I take it nobody has seen the lovely animations of stacks that BBC News/Sky News created when there was "all that fog planes could not go into" around Heathrown? 
The only way to reduce holding is to timetable a somewhat less than 100% of theoretical capacity. I don't work in ATC but attended a talk by David McMillan a few weeks ago where he said that airlines might even be willing to do this. We shall see!
I've often wondered if it might be possible to use advanced computerisation to plot flight plans to the minute and avoid the need for holding en route but it would require very powerful computers, unified ATC and most implausably co-operation of the weather. Think what a thunder cell would do!
A third runway would help if it was not fully utilised but I would hope that all aircraft using it would park at a terminal to the north of the existing northerly runway - a Heathrow North if you like. Otherwise vast amounts of kerosene will be burnt taxiing. I am surprised that average taxi out time is at LHR is only 20 minutes but it still quicker than some airports - such as JFK (and AMS taxiing in).
I've often wondered if it might be possible to use advanced computerisation to plot flight plans to the minute and avoid the need for holding en route but it would require very powerful computers, unified ATC and most implausably co-operation of the weather. Think what a thunder cell would do!
A third runway would help if it was not fully utilised but I would hope that all aircraft using it would park at a terminal to the north of the existing northerly runway - a Heathrow North if you like. Otherwise vast amounts of kerosene will be burnt taxiing. I am surprised that average taxi out time is at LHR is only 20 minutes but it still quicker than some airports - such as JFK (and AMS taxiing in).
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Peter47. Years ago Heathrow had a scheduling committee, which included reps from ATC, airlines, airport authority, etc. It was designed to prevent major holding by spreading the schedules. I don't know if it still functions but it didn't work too well as most pax want to travel either morning or evening.. Trying to organise every flight to arrive or depart at a specified time to avoid delays would be just about impossible given the number of variables in the equation. At least twice attempts have been made to partially "computerise" the approach sequence at Heathrow but both failed because the machines could not cope with the variables. It's like saying if we give every commuting car driver a precise time to leave home we can avoid the hold-ups on Battersea Bridge....
It still does in the form of Airport Co-ordination Ltd. They have a good website Airport Coordination Limited - Welcome to ACL which has statistics which show available and used movements per hour (basically the same). Just to think when T4 was opened the agreement was to limit ATMs to, I think from memory, 265,000. That didn't last long!
Mind you in those days sector times were much shorter than they are today - 60 minutes in each direction for AMS & CDG. I wonder how much extra the longer block times cost airlines in fuel, crew, additional aircraft and so on. Still the airlines must have thought it worthwhile whilst agreeing to higher hourly limits. Indeed the likes of VS really owe their slot holdings to the increase in movements that has occurred.
Actually in my experience the problem is isn't so much holding waiting to land as waiting to take off, but aircraft stil burn fuel whilst taxiing.
Mind you in those days sector times were much shorter than they are today - 60 minutes in each direction for AMS & CDG. I wonder how much extra the longer block times cost airlines in fuel, crew, additional aircraft and so on. Still the airlines must have thought it worthwhile whilst agreeing to higher hourly limits. Indeed the likes of VS really owe their slot holdings to the increase in movements that has occurred.
Actually in my experience the problem is isn't so much holding waiting to land as waiting to take off, but aircraft stil burn fuel whilst taxiing.
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P47
I think the figure was 275,000 ATM's, and I believe this was broken in the first year T4 was operational. Guess what, no action was taken by the Government or BAA to reduce the number of flights.
I think the figure was 275,000 ATM's, and I believe this was broken in the first year T4 was operational. Guess what, no action was taken by the Government or BAA to reduce the number of flights.
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I think however its been put by the politicians/journalists, HD is somewhat missing the point of the statement that is made, Holding regardless of where it occurrs, even if it was in the middle of the atlantic does have negative enviromental effects. Quite simply because the aircraft is burning more fuel than it would if it took off flew direct and then landed. More fuel=more pollution, more fuel=less fuel left, more fuel=greater cost to pax, more fuel=airline going bust. The highest proportion of the cost of operation to most flights is fuel, not crew, a/c maintenance or the like.
ATC may think they are the "skygods" but keeping them apart isnt the only thing to consider because increased holding, delays, could actually mean that a few more airlines go bust and then there be less to worry about to actually keep apart! So wherever they hold for heathrow, holding does need to be reduced for more than just enviromental reasons, quite simply to keep ATC in a job!
regards PETER47's post and computers to calculate and plot flightplans, sorry but too late to patent your idea, its already being worked on now, NATS and various parts of europe are already working on tools, to do just this, parts of IFACTs and other tools, will help control profiles. There is also whats been around for years, Flow control (or Network Management). But just as peter mentions thunder storm cells dont fit into computer models so well, as they tend to not obey their slots! There will never be a perfect system, as like as also been mentioned all business men want to fly at the same time to get to or back from their meeting, but thats where management of non-business flights get pushed away from these times helps.
Its interesting point to look at though, one argument could be go the airbus way, bigger planes, less flights, yet enviromentalists, then argue they use more fuel, are noisy blah blah blah. So go the boeing way and develop a smaller 787 that is "greener" to operate, but then you fly more of them, and end up with holding again so end up using more fuel. Its all gettin a bit distorted this green thinking, its like buying some far eastern made electric car, the government will say how great you are for driving one, it doesnt pollute the atmosphere, use fuel blah blah blah....Ummm apart from the toxic substances in the batteries that damaged the enviroment to produce them, the fact that it cost massive amounts of Carbon emmisions to manufacture and then ship it half way across the world in a oil burning ship, the batteries made somewhere else and shipped in....and then finally, the electric you power it with, was yes you guessed it, generated from a coal burning power station! lol
So I suppose to summarise bugger the enviroment, reduce holding at EGLL for far better reasons, to keep those that are alive now in jobs, save us time so we can enjoy the planet while its still here, because as history as shown dominant species get wipped out everynow and then anyway and more likely to be because of something else other than just a bit of natural global warming/cooling. We are due a reversal of the poles, yellowstone park should errupt soon, some erruption is due in the atlantic which will release massive amounts of frozen methane, oh and there some trillion trillion amounts of rock hurtling around space thats got our name on it. Or more likely Bacteria will finally see us off due to overuse of Anti-biotics.
ATC may think they are the "skygods" but keeping them apart isnt the only thing to consider because increased holding, delays, could actually mean that a few more airlines go bust and then there be less to worry about to actually keep apart! So wherever they hold for heathrow, holding does need to be reduced for more than just enviromental reasons, quite simply to keep ATC in a job!
regards PETER47's post and computers to calculate and plot flightplans, sorry but too late to patent your idea, its already being worked on now, NATS and various parts of europe are already working on tools, to do just this, parts of IFACTs and other tools, will help control profiles. There is also whats been around for years, Flow control (or Network Management). But just as peter mentions thunder storm cells dont fit into computer models so well, as they tend to not obey their slots! There will never be a perfect system, as like as also been mentioned all business men want to fly at the same time to get to or back from their meeting, but thats where management of non-business flights get pushed away from these times helps.
Its interesting point to look at though, one argument could be go the airbus way, bigger planes, less flights, yet enviromentalists, then argue they use more fuel, are noisy blah blah blah. So go the boeing way and develop a smaller 787 that is "greener" to operate, but then you fly more of them, and end up with holding again so end up using more fuel. Its all gettin a bit distorted this green thinking, its like buying some far eastern made electric car, the government will say how great you are for driving one, it doesnt pollute the atmosphere, use fuel blah blah blah....Ummm apart from the toxic substances in the batteries that damaged the enviroment to produce them, the fact that it cost massive amounts of Carbon emmisions to manufacture and then ship it half way across the world in a oil burning ship, the batteries made somewhere else and shipped in....and then finally, the electric you power it with, was yes you guessed it, generated from a coal burning power station! lol
So I suppose to summarise bugger the enviroment, reduce holding at EGLL for far better reasons, to keep those that are alive now in jobs, save us time so we can enjoy the planet while its still here, because as history as shown dominant species get wipped out everynow and then anyway and more likely to be because of something else other than just a bit of natural global warming/cooling. We are due a reversal of the poles, yellowstone park should errupt soon, some erruption is due in the atlantic which will release massive amounts of frozen methane, oh and there some trillion trillion amounts of rock hurtling around space thats got our name on it. Or more likely Bacteria will finally see us off due to overuse of Anti-biotics.
