ATC Question?
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ATC Question?
Hi guys and gals,
I have a question regarding ATC. Hopefully someone can answer and it may sound daft but I'm interesed!
When a plane is on approach to say LHR and the ATCO reads out instructions for it to descend and the direction etc. Does the ATCO calculate this info or does the computer system work out the headings to fly and the flight levels it will need to descend to?
I understand some ATC but not all.
Cheers...
I have a question regarding ATC. Hopefully someone can answer and it may sound daft but I'm interesed!
When a plane is on approach to say LHR and the ATCO reads out instructions for it to descend and the direction etc. Does the ATCO calculate this info or does the computer system work out the headings to fly and the flight levels it will need to descend to?
I understand some ATC but not all.
Cheers...
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with respect to LHR it comes from saying the same things over and over and over again!
Really, the years of training mean the controller can use his/her skill and judgement to do it just by using the info provided by the radar screen.
There is no computer, not in NATS, that tells the controller what to do otherwise why need a controller in the first place?
Really, the years of training mean the controller can use his/her skill and judgement to do it just by using the info provided by the radar screen.
There is no computer, not in NATS, that tells the controller what to do otherwise why need a controller in the first place?
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uk20.. Don't worry; you're not the first one to ask the question. I showed a BA Command Course (potential Captains) around Heathrow ATC some years ago. One of them whispered: "Where's the computer that tells you what to tell us?" I simply pointed at my head and he was taken aback!
Controllers are highly trained individuals in many aspects of ATC. Radar Control is but one and it is a serious skill. There are, of course, certain procedures to be followed, eg points at which aircraft may be descended, etc., but the basic instructions are decided by the individual ATCO with no assistance except his training.
NATS have tried various types of computer assistance to make the spacing task at busy aerodromes "better" but none yet as been able to beat properly trained and experienced controllers.
Hope that helps...
Controllers are highly trained individuals in many aspects of ATC. Radar Control is but one and it is a serious skill. There are, of course, certain procedures to be followed, eg points at which aircraft may be descended, etc., but the basic instructions are decided by the individual ATCO with no assistance except his training.
NATS have tried various types of computer assistance to make the spacing task at busy aerodromes "better" but none yet as been able to beat properly trained and experienced controllers.
Hope that helps...
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So if I can think of a system that will generate all this info....I could make millions.
As I said I wasn't sure but wow that is pretty good. So as the aircraft goes through approach and you guys tell it what to do.
When the flight joins the ILS will this Landing System join it up exactly to the runway incase someone was a little out of line?
As I said I wasn't sure but wow that is pretty good. So as the aircraft goes through approach and you guys tell it what to do.
When the flight joins the ILS will this Landing System join it up exactly to the runway incase someone was a little out of line?
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ILS, simply put is 4 beams of energy. The localiser, this is generated from the metal structure at the far end of the runway. It is two beams of energy that overlap in the middle, so if the aircraft is receiving equal amounts of the localiser then it is on the centreline. two much of one or the other and it is left or right of the centreline.
The glideslope, the same as the localiser pretty much. You can see a vertical structure about one third from the start of the runway. It beams out two amounts of energy. Too much of the lower one and you are below the correct glidepath, too much of the upper one, obviously too high! Equal amounts mean you are on a perfect 3 degree approach path, not at all airfields, and you will hit the runway on the money.
Obviously this is in simple terms but I hope some others will add to this!
http://en.wikipedia.org/wiki/Instrument_landing_system
This has a good picture
The glideslope, the same as the localiser pretty much. You can see a vertical structure about one third from the start of the runway. It beams out two amounts of energy. Too much of the lower one and you are below the correct glidepath, too much of the upper one, obviously too high! Equal amounts mean you are on a perfect 3 degree approach path, not at all airfields, and you will hit the runway on the money.
Obviously this is in simple terms but I hope some others will add to this!
http://en.wikipedia.org/wiki/Instrument_landing_system
This has a good picture
Last edited by MancBoy; 18th Jul 2007 at 21:21.
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Hey, MancBoy, almost sounds like you know what you're talking about! 
Very surprised to see an area type know what goes on at an airfield!!!!
uk20,
I'm afraid probably not. As others have said, it's been tried before. The most recent attempt was named FAST and it was found that it was being outperformed by humans. Too many variables, I'd imagine.
And then of course there's a whole new argument about ATCOs getting to rely on a computer to tell them how to do their job, and then one day the computer stops..................
Very surprised to see an area type know what goes on at an airfield!!!!
uk20,
So if I can think of a system that will generate all this info....I could make millions.
And then of course there's a whole new argument about ATCOs getting to rely on a computer to tell them how to do their job, and then one day the computer stops..................
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Somewhere, and I'm thinking it could be the RAF museum at Hendon, there's an excellent example of how ILS operates, but using old tech.
The first attempt at a localiser used good old radio braodcasts. Two lobes of radio energy were broadcast using directional antennae. Both simply broadcast a beep, with spaces between beeps of equal length to the beep itself. The beeps of each lobe were perfectly out of phase with one another but were broadcast on the same frequency, and here's the clever bit - the lobes had a small area of overlap. If you were in the overlap, you heard a solid sound with no gaps, and you were in the groove!
ILS is much the same in concept except with more of an overlap and the phase difference is measured by an instrument (that'd be the ILS receiver) in the cockpit. The sweet spot is still right in the middle, and the needle on the receiver's dial (or bug or whatever in a glass cockpit) shows you where you are in relation to that sweet spot. Left a bit, right a smidge, etc etc.
Going back to uk20's third post - you say the aircraft "goes through approach". Actually an aircraft of the airliner variety will usually spend every second of every flight, whether in the approach phase or not, under the control of ATC. There are more area/en-route (the latter name is used in North America) controllers than there are approach/terminal (same again) controllers, because aircraft spend a lot more time and travel a lot more distance in the cruise phase than the approach phase. The instructions we give aren't just climb/descend and turn left/turn right. Speed control is an essential element too. Then are tower controllers who usually have a radar screen or two nearby but actually control on the basis of what they can see out of the window. If you really want to know more, pay a visit to your nearest tower. If you can make it to one with an approach unit on site, so much the better.
The first attempt at a localiser used good old radio braodcasts. Two lobes of radio energy were broadcast using directional antennae. Both simply broadcast a beep, with spaces between beeps of equal length to the beep itself. The beeps of each lobe were perfectly out of phase with one another but were broadcast on the same frequency, and here's the clever bit - the lobes had a small area of overlap. If you were in the overlap, you heard a solid sound with no gaps, and you were in the groove!
ILS is much the same in concept except with more of an overlap and the phase difference is measured by an instrument (that'd be the ILS receiver) in the cockpit. The sweet spot is still right in the middle, and the needle on the receiver's dial (or bug or whatever in a glass cockpit) shows you where you are in relation to that sweet spot. Left a bit, right a smidge, etc etc.
Going back to uk20's third post - you say the aircraft "goes through approach". Actually an aircraft of the airliner variety will usually spend every second of every flight, whether in the approach phase or not, under the control of ATC. There are more area/en-route (the latter name is used in North America) controllers than there are approach/terminal (same again) controllers, because aircraft spend a lot more time and travel a lot more distance in the cruise phase than the approach phase. The instructions we give aren't just climb/descend and turn left/turn right. Speed control is an essential element too. Then are tower controllers who usually have a radar screen or two nearby but actually control on the basis of what they can see out of the window. If you really want to know more, pay a visit to your nearest tower. If you can make it to one with an approach unit on site, so much the better.
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Cheers for the info guys.
Lock n Load I could go to LHR itself as that has a lot going on.
I see you are in Dubai, I have just got back from Dubai. I love Dubai....awesome place! I think anyway!
Lock n Load I could go to LHR itself as that has a lot going on.
I see you are in Dubai, I have just got back from Dubai. I love Dubai....awesome place! I think anyway!
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Gonzo, I did do and pass an aerodrome course back in 93!
My course, 88, was also the last one to have to do Radar Theory which was like doing a mini physics A Level. Nightmare. Still got 94% though!
Stood me in good stead though, use it every day.
I don't think so!
My course, 88, was also the last one to have to do Radar Theory which was like doing a mini physics A Level. Nightmare. Still got 94% though!
Stood me in good stead though, use it every day.
I don't think so!
