speed control
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speed control
hi all,
can someone please tell me where i can find information about speed control? i'm looking for something on the net. any good websites?
thank you
can someone please tell me where i can find information about speed control? i'm looking for something on the net. any good websites?
thank you
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Hi,
You won't find a better source of reference than the combined knowledge of the many controllers worldwide who post on this forum.
What do you want to know?
There are certain legal speed limits, other than that speed control is applied at the discretion of the controller (especially in the approach environment).
Ask away and I'm sure all your questions will be answered
You won't find a better source of reference than the combined knowledge of the many controllers worldwide who post on this forum.
What do you want to know?
There are certain legal speed limits, other than that speed control is applied at the discretion of the controller (especially in the approach environment).
Ask away and I'm sure all your questions will be answered
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Speed control in the UK is all detailed in the ANO (Rule 23 of the Rules of the Air within the ANO).
CAP 393 - The ANO
The AIM is published by the US FAA here.
Hope this helps.
CAP 393 - The ANO
The AIM is published by the US FAA here.
Hope this helps.
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thanks guys
Radar707, i have a lot of questions.
my first is if two aircraft are descending and are passing different levels, speed imposed will not work, am i correct?
and i can't find the materials i wanted on the websites above.
Radar707, i have a lot of questions.
my first is if two aircraft are descending and are passing different levels, speed imposed will not work, am i correct?
and i can't find the materials i wanted on the websites above.
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van der ... you are correct. Using anything but Mach number with aircraft at different levels is a waste of time and sometimes positively dangerous.
I'd like to know if you do find any useful info.
I'd like to know if you do find any useful info.
More than just an ATCO
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Taking a case you may be familiar with; inbounds EHAM from the North at high levels.
The Letter of agreement between LvlNl (Luchtverkeersleiding Nederland) and Eurocontrol requires that the traffic be at FL260 at the FIR bdy. (22n.m. N of EEL). In practice FL 260 at EEL is acceptable until it gets really busy at ARTIP.
The ACC prefers the traffic in trail so the clearance is often, " Descend FL260, level at EEL, when within range IAS 290 knots."
Please note "Descend FL260," NOT "Descend 260," which, in high traffic, greatly increases the pucker factor.
The speeds can then be adjusted as they approach EEL to ensure the 5 miles separation.
Sometimes flights are transferred on parallel headings, with differing speeds, which ensures the 5n.m. is rapidly ensured
In the descent, vertical rates are often used, where two same type aircraft are on top of each other, the one deemed to be second will be dropped first, with a rate and speed limitation
At other times traffic may be requested to keep up the speed in the descent. This also means an earlier start to the descent, but an earlier arrival at EEL.
Hope that this was understandable after a traditional Christmas dinner. If you are an aviation professional a visit to the Centre at Maastricht can always be arranged, it's much easier to demonstrate it than explain it.
Prettige Kerst verder, met vriendelijke groeten
Lon More,
Here since before Pontius was a Pilot or Mortus was a Rigger
The Letter of agreement between LvlNl (Luchtverkeersleiding Nederland) and Eurocontrol requires that the traffic be at FL260 at the FIR bdy. (22n.m. N of EEL). In practice FL 260 at EEL is acceptable until it gets really busy at ARTIP.
The ACC prefers the traffic in trail so the clearance is often, " Descend FL260, level at EEL, when within range IAS 290 knots."
Please note "Descend FL260," NOT "Descend 260," which, in high traffic, greatly increases the pucker factor.
The speeds can then be adjusted as they approach EEL to ensure the 5 miles separation.
Sometimes flights are transferred on parallel headings, with differing speeds, which ensures the 5n.m. is rapidly ensured
In the descent, vertical rates are often used, where two same type aircraft are on top of each other, the one deemed to be second will be dropped first, with a rate and speed limitation
At other times traffic may be requested to keep up the speed in the descent. This also means an earlier start to the descent, but an earlier arrival at EEL.
Hope that this was understandable after a traditional Christmas dinner. If you are an aviation professional a visit to the Centre at Maastricht can always be arranged, it's much easier to demonstrate it than explain it.
Prettige Kerst verder, met vriendelijke groeten
Lon More,
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vdv
The speed restriction imposed will work - the result, though, could be unexpected!
I know, from experience, that just by giving 2 aircraft the same descent speed does not mean that they no longer require radar monitoring. However, there are a few tricks that we've all picked up along the way to make speed control more effective.
First let me point out that I'm talking purely from an area control point of view using speed control down to about FL150, and bear in mind that it's not my aim to put a stream of aircraft all exactly 5 miles in trail (our MATS pt 2 doesn't allow that for silent handovers)
When I'm teaching speed control, these are the gems to pass on;
Never try to make a gap from nothing using only speed control, you'll need more airspace than you've got! Maintaining a gap using speed control is far easier.
If 1 of your restricted aircraft starts the descent, tell the other one to start to! (as you rightly say - seen to many times an earlier descender has been chomped by the 1 behind both doing 250kts)
Give the required speed as early as possible, in this modern era we are overloaded with level restrictions that aircrew need to take into account when planning their profiles.
If you have it, use some leeway ie. if your aircraft are 10 miles in trail give the first a descent speed of "300 or better" and the second "280 or less" following the above rules should then work a treat!
Finally, look what's happening ahead - again too many times have I seen my fellow ATCO's do some wonderful streaming using vast ranges of speed only for all the aircraft concerned to end up flying in circles round the hold for 20 minutes! beautiful but pointless!
Once again let me say that I'm on the Area side of things, the terminal and approach guys may have a different viewpoint.
Just as an add on - not sure I fully agree with a previous comment about "using anything but a mach No. with aircraft at different levels is a waste of time" I feel that the only time you are guaranteed success using mach number restrictions is if the aircraft are at the same level.
if two aircraft are descending and are passing different levels, speed imposed will not work, am i correct?
I know, from experience, that just by giving 2 aircraft the same descent speed does not mean that they no longer require radar monitoring. However, there are a few tricks that we've all picked up along the way to make speed control more effective.
First let me point out that I'm talking purely from an area control point of view using speed control down to about FL150, and bear in mind that it's not my aim to put a stream of aircraft all exactly 5 miles in trail (our MATS pt 2 doesn't allow that for silent handovers)
When I'm teaching speed control, these are the gems to pass on;
Never try to make a gap from nothing using only speed control, you'll need more airspace than you've got! Maintaining a gap using speed control is far easier.
If 1 of your restricted aircraft starts the descent, tell the other one to start to! (as you rightly say - seen to many times an earlier descender has been chomped by the 1 behind both doing 250kts)
Give the required speed as early as possible, in this modern era we are overloaded with level restrictions that aircrew need to take into account when planning their profiles.
If you have it, use some leeway ie. if your aircraft are 10 miles in trail give the first a descent speed of "300 or better" and the second "280 or less" following the above rules should then work a treat!
Finally, look what's happening ahead - again too many times have I seen my fellow ATCO's do some wonderful streaming using vast ranges of speed only for all the aircraft concerned to end up flying in circles round the hold for 20 minutes! beautiful but pointless!
Once again let me say that I'm on the Area side of things, the terminal and approach guys may have a different viewpoint.
Just as an add on - not sure I fully agree with a previous comment about "using anything but a mach No. with aircraft at different levels is a waste of time" I feel that the only time you are guaranteed success using mach number restrictions is if the aircraft are at the same level.
Last edited by StillDark&Hungry; 27th Dec 2003 at 13:40.
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what if two aircraft are 10 nm apart, the leading say at level 190,
the second at level 280, and i want to maintain the 10 nm spacing.
will 300kts and 280kts on descend work considering the level difference?
the second at level 280, and i want to maintain the 10 nm spacing.
will 300kts and 280kts on descend work considering the level difference?
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Van Der,
I don't work enroute but at an approach control.
If I have two acft, both descending and being vectored for an approach and lets say that acft #1 is descending through 110 at 210 kts (ground speed) to 40, and acft two checks on at 140 doing about 320 kts, and I currently have approximately 10 miles spacing between them that I want to maintain.
I will have acft two reduce speed to 210 kts (acft #1 speed), then descend and maintain an altitude. When acft #2 reduces to 210 (and yes it takes a few miles) the pilot will then descend to the issued altitude and I should maintain the 10 miles spacing or fairly close to it. Now if acft #2 takes his sweet time slowing up then I will have to take other action but the end result will be to maintain or regain the needed spacing.
Mike
NATCA FWA
I don't work enroute but at an approach control.
If I have two acft, both descending and being vectored for an approach and lets say that acft #1 is descending through 110 at 210 kts (ground speed) to 40, and acft two checks on at 140 doing about 320 kts, and I currently have approximately 10 miles spacing between them that I want to maintain.
I will have acft two reduce speed to 210 kts (acft #1 speed), then descend and maintain an altitude. When acft #2 reduces to 210 (and yes it takes a few miles) the pilot will then descend to the issued altitude and I should maintain the 10 miles spacing or fairly close to it. Now if acft #2 takes his sweet time slowing up then I will have to take other action but the end result will be to maintain or regain the needed spacing.
Mike
NATCA FWA
Slow to 210 and a descent is going to yield a pretty slow descent rate, even with the boards hanging out. All this is made even worse if the wings and cowl anti ice is operating. It can be done of course, just don't expect us to come out of the sky like a brick.
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vdv
With reference to your last example - the simple answer is no, it won't work! I'm afraid to say I can't give you a simple mathematical equation to say why, because of all the variables. (No-one's mentioned wind speeds yet! Oops there we go!)
In the situation you gave you would have to use an additional form of separation until you had the 2 aircraft at similar levels.
I know it slightly contradicts what I said in my previous post, but if the aircraft in your example were, say, 5 miles apart it may be prudent to make the higher one number 1, and let them overtake. ie. 250kts @ FL190 is not hugely restrictive in level flight, give the 2nd a late descent from FL280 and, depending on type, obviously, they could easily give 310kts+, so with a difference of 60+ IAS, and the altitude difference you could get quite a quick pass especially with a bit of fancy vectoring!
Remember, as West Coast rightly points out, asking a plane to "Go down & Slow down" at the same time, without notice, may cause some frowns on the flightdeck
Use Newton's laws
the aircraft at FL280 has a hell of a lot more potential energy - may be easier to use it than waste it
I'm getting into this
keep 'em coming.
With reference to your last example - the simple answer is no, it won't work! I'm afraid to say I can't give you a simple mathematical equation to say why, because of all the variables. (No-one's mentioned wind speeds yet! Oops there we go!)
In the situation you gave you would have to use an additional form of separation until you had the 2 aircraft at similar levels.
I know it slightly contradicts what I said in my previous post, but if the aircraft in your example were, say, 5 miles apart it may be prudent to make the higher one number 1, and let them overtake. ie. 250kts @ FL190 is not hugely restrictive in level flight, give the 2nd a late descent from FL280 and, depending on type, obviously, they could easily give 310kts+, so with a difference of 60+ IAS, and the altitude difference you could get quite a quick pass especially with a bit of fancy vectoring!
Remember, as West Coast rightly points out, asking a plane to "Go down & Slow down" at the same time, without notice, may cause some frowns on the flightdeck
Use Newton's laws
the aircraft at FL280 has a hell of a lot more potential energy - may be easier to use it than waste it I'm getting into this
keep 'em coming.
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van der... are you a controller? If so, it might be an idea for us to put some typical descent mach/IAS numbers on this thread for you?
You COULD then dictate something like 'maintain 0.74 to 300 kts' or similar when really necessary which would cover the problem for aircraft that are not too dissimilar, although I fancy SDH has a more practical solution!
You COULD then dictate something like 'maintain 0.74 to 300 kts' or similar when really necessary which would cover the problem for aircraft that are not too dissimilar, although I fancy SDH has a more practical solution!
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vdv
Went back to the scope after my last post and was able to glean the perfect example for you, 2 aircraft following the same track about 30 miles in trail. The first, obviously early, requested an early 250kt descent - the second was unrestricted.
At FL190 the first was still indicating 250 and was showing a
Ground speed of 345. At about the same time the second was passing FL280 so, when asked, gave an IAS of 310kts which showed on radar as a Ground speed of 485
Went back to the scope after my last post and was able to glean the perfect example for you, 2 aircraft following the same track about 30 miles in trail. The first, obviously early, requested an early 250kt descent - the second was unrestricted.
At FL190 the first was still indicating 250 and was showing a
Ground speed of 345. At about the same time the second was passing FL280 so, when asked, gave an IAS of 310kts which showed on radar as a Ground speed of 485
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van der vart
First rule....know your aircraft and their capabilities. There is no second rule; however there is a rule of thumb that has served me well for some considerable time /// 2% per thousand feet will give a rough guide to the relationship between indicated airspeed and True airspeed. e.g. 250 knots indicated at 20,000feet will give 350 knots True [ 20x2=40, add 40%]. 250 knots at 30,000feet will give 400 knots True [ 30x2=60, add 60%]. With heavy jets I have found that they will comply with a speed restriction in knots from quite a high level as long as it is not ridiculous e.g. 300 knots indicated at FL290, which would be about 475 knots True. Obviously not all aircraft can do this and for streaming you may need speeds of about 280/270 until you're in thicker air, say FL270 and below. Difficult to teach so I never use it with trainees, and it isn't exactly written in the manual either. Recommend some flightdeck trips or just try it a couple of times.....or dare I say...chat with the pilots if workload and traffic permits....they seem like nice people!
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van der vart
Sorry ....me again. If you want to slow traffic you will be amazed how slow they can go; a heavy has no trouble coming back to 250 knots, and sometimes they ask for it to avoid excessive holding or ground/stand congestion. They can come back further to 230 or even 220.....but you risk disrupting traffic flow due catch-up.....whatever you do please don't abuse the helpful pilot.....at reduced speed he may need a lot of miles to get the height off and will not thank you for a last minute dive to make a late level instruction......in other words plan well ahead and do not forget to look behind for what is coming next.
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Further to previous posts, pegging Mach Nos is the same as pegging IAS - they will only be the same at the same level.
If the aircraft are at different levels, then you need to think in terms of TAS (of course, you don't use TAS with the aircraft). And that's to say nothing on the effects of wind gradient!
If the aircraft are at different levels, then you need to think in terms of TAS (of course, you don't use TAS with the aircraft). And that's to say nothing on the effects of wind gradient!
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Just for my 2 cents worth Van,
Don't ever forget that aircraft can't slow down well and go down well at the same time..........especially if there is a tight level requirement for whatever reason (airspace, holding facility). You'll really endeer yourself with an instruction to a jet cruising at 280ish knots at FL200 "Reduce speed 220 kts and descend FL130".................throw in an expidite request and see what happens!.
Also, as has been mentioned here by SD&H, I have seen some brilliant efforts at streaming jets 5 mile in trail, with the first guy screaching along at +300kts to be told he'll have to hold. Through no fault of the pilot, seen some great hold entry procedures from some poor guy trying to wash off nearly 100 kts in speed.
All the best,
Don't ever forget that aircraft can't slow down well and go down well at the same time..........especially if there is a tight level requirement for whatever reason (airspace, holding facility). You'll really endeer yourself with an instruction to a jet cruising at 280ish knots at FL200 "Reduce speed 220 kts and descend FL130".................throw in an expidite request and see what happens!
. Also, as has been mentioned here by SD&H, I have seen some brilliant efforts at streaming jets 5 mile in trail, with the first guy screaching along at +300kts to be told he'll have to hold. Through no fault of the pilot, seen some great hold entry procedures from some poor guy trying to wash off nearly 100 kts in speed.
All the best,