Minimum Separation on Approach at LHR
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Well yeah...the Dash 8 isn't RVSM approved..But I've asked a number of people the same question and Wake Vortex just kept coming up!?!We like thread drifts!!!!!!
Good heading, here's one for you...Who controls the tracks on the Eastern side of the Atlantic???
Good heading, here's one for you...Who controls the tracks on the Eastern side of the Atlantic???
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WV
excuse my ignorance on this, but why is the limit set at 4nm for heavy immediately followed by heavy (or any other aircraft)? and are those limits ever broken?
thanks
Ian Shoesmith
BBC News
thanks
Ian Shoesmith
BBC News
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Aircraft create wake vortex from each wingtip.
The violence of this is dependent on the weight of the aircraft, so we provide more separation for a smaller aircraft following a larger one.
For example, at Heathrow, a 747 following a 747 would be 4 miles. A 737 following a 747 would be 5 miles. However, a 747 following behind a 737 does not require any vortex separation, because in that case the smaller aicraft is in front.
The violence of this is dependent on the weight of the aircraft, so we provide more separation for a smaller aircraft following a larger one.
For example, at Heathrow, a 747 following a 747 would be 4 miles. A 737 following a 747 would be 5 miles. However, a 747 following behind a 737 does not require any vortex separation, because in that case the smaller aicraft is in front.
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Dear Shoey,
Imagine firemen sliding down their pole. You jump onto the pole before the previous guy's reached the bottom, and you know you won't get off before the next man's bearing down on you from above.
Luckily the firemen are skilled acrobats, and we get it right most of the time
Imagine firemen sliding down their pole. You jump onto the pole before the previous guy's reached the bottom, and you know you won't get off before the next man's bearing down on you from above.
Luckily the firemen are skilled acrobats, and we get it right most of the time
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Gonzo...I assume your comments are based on limits set for controlled airspace??
Because outside controlled airspace the distance between all aircrafts are 5nm right? Regardless of size and wake vortex?
Or...Do smaller aircrafts travelling behind bigger aircrafts (E.g. Dash 8 travelling behing a B757) have to have a bigger distance than 5nm in uncontrolled airspace??
Because outside controlled airspace the distance between all aircrafts are 5nm right? Regardless of size and wake vortex?
Or...Do smaller aircrafts travelling behind bigger aircrafts (E.g. Dash 8 travelling behing a B757) have to have a bigger distance than 5nm in uncontrolled airspace??
We don't use Ausy rules here in blighty - here's a simple table of the arrival spacings I have to apply
Leading.......Following.............Minimum Distance...Minimum Distance
Aircraft.......Aircraft................MATS 1.................London MATS 2
SUPER........SUPER...................4 miles
(A380)........HEAVY..................6 miles
.................MEDIUM................8 miles/3 minutes
.................SMALL..................8 miles/3 minutes
.................LIGHT.................10 miles/4 minutes
HEAVY........HEAVY..................4 miles.................4 miles
.................UPPER MEDIUM.......5 miles.................5 miles
.................MEDIUM................5 miles.................5 miles
.................SMALL..................6 miles................ 6 miles
.................LIGHT...................8 miles.................7 miles
UPPER.........UPPER MEDIUM.......4 miles.................3 miles
MEDIUM.......MEDIUM................4 miles.................4 miles
.................SMALL..................4 miles..................4 miles
.................LIGHT...................6 miles..................6 miles
MEDIUM......MEDIUM................3 miles...................N/R
.................SMALL..................4 miles..................3 miles
.................LIGHT...................6 miles..................5 miles
SMALL........MEDIUM................3 miles..................N/R
.................SMALL..................3 miles..................N/R
.................LIGHT...................4 miles..................3 miles
Upper medium = B757, DC8, B707, IL62 or VC10
N/R - Not required
UK categories by MTOW
Heavy 136000+ kg; Medium 40000-136000 kg; Small 17000-40000 kg; Light -1700kg.
Although these are minima for IFR final approach spacing it is recognised that as aircraft slow down durng the final stages of approach these minima will be slightly erroded so the spacing is normally applied until 4 nm final by use of rigid speed control.
I don't believe that stats are kept of the number of times less than minimum spacing is applied (doesn't happen very often) but pilots are always encouraged to report a vortex wake encounter in order that the phenomenon can be better understood. I'd probably have 2 pilots a year filing a vortex report and that would normally be when the minimum spacing has been applied. The minima are to reduce the likelyhood of a vortex encounter, they do not claim to erradicate all chance of an encounter.
VFR traffic is allowed to self position behind heavier aircraft. We use the phraseology "...caution vortex wake, the recommended spacing is x miles." and allow the pilot to use judgemet as to how much spacing to apply.
Remind me never to try to PPRuNe a table again
Leading.......Following.............Minimum Distance...Minimum Distance
Aircraft.......Aircraft................MATS 1.................London MATS 2
SUPER........SUPER...................4 miles
(A380)........HEAVY..................6 miles
.................MEDIUM................8 miles/3 minutes
.................SMALL..................8 miles/3 minutes
.................LIGHT.................10 miles/4 minutes
HEAVY........HEAVY..................4 miles.................4 miles
.................UPPER MEDIUM.......5 miles.................5 miles
.................MEDIUM................5 miles.................5 miles
.................SMALL..................6 miles................ 6 miles
.................LIGHT...................8 miles.................7 miles
UPPER.........UPPER MEDIUM.......4 miles.................3 miles
MEDIUM.......MEDIUM................4 miles.................4 miles
.................SMALL..................4 miles..................4 miles
.................LIGHT...................6 miles..................6 miles
MEDIUM......MEDIUM................3 miles...................N/R
.................SMALL..................4 miles..................3 miles
.................LIGHT...................6 miles..................5 miles
SMALL........MEDIUM................3 miles..................N/R
.................SMALL..................3 miles..................N/R
.................LIGHT...................4 miles..................3 miles
Upper medium = B757, DC8, B707, IL62 or VC10
N/R - Not required
UK categories by MTOW
Heavy 136000+ kg; Medium 40000-136000 kg; Small 17000-40000 kg; Light -1700kg.
Although these are minima for IFR final approach spacing it is recognised that as aircraft slow down durng the final stages of approach these minima will be slightly erroded so the spacing is normally applied until 4 nm final by use of rigid speed control.
I don't believe that stats are kept of the number of times less than minimum spacing is applied (doesn't happen very often) but pilots are always encouraged to report a vortex wake encounter in order that the phenomenon can be better understood. I'd probably have 2 pilots a year filing a vortex report and that would normally be when the minimum spacing has been applied. The minima are to reduce the likelyhood of a vortex encounter, they do not claim to erradicate all chance of an encounter.
VFR traffic is allowed to self position behind heavier aircraft. We use the phraseology "...caution vortex wake, the recommended spacing is x miles." and allow the pilot to use judgemet as to how much spacing to apply.
Remind me never to try to PPRuNe a table again
Last edited by Dan Dare; 15th Feb 2008 at 13:20.
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Greg ATCO,
I think your name may be misleading . . . . . (and not the Greg bit)
Aircraft outside controlled airspace are uncontrolled. . . . . they can fly 2cm away from each other if they want to.
I think your name may be misleading . . . . . (and not the Greg bit)
Aircraft outside controlled airspace are uncontrolled. . . . . they can fly 2cm away from each other if they want to.
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BOBBLEHAT, I wonder if your stated profession may be misleading. 
In the UK we have some wonderful, if completely non-standard, services which provide 'control' and separation outside CAS. Granted, to most sane-minded controllers, and to ICAO, this is a peculiarity, and one which creates many problems, but it is a fact. As far as I am aware, with many years of working such an environment, wake vortex spacings should be applied to those aircraft if the circumstances meet the criteria specified in MATS Part 1. In reality, this will rarely happen but I think the wake vortex spacing rules still apply.
Sometimes I feel so proud to be British.
In the UK we have some wonderful, if completely non-standard, services which provide 'control' and separation outside CAS. Granted, to most sane-minded controllers, and to ICAO, this is a peculiarity, and one which creates many problems, but it is a fact. As far as I am aware, with many years of working such an environment, wake vortex spacings should be applied to those aircraft if the circumstances meet the criteria specified in MATS Part 1. In reality, this will rarely happen but I think the wake vortex spacing rules still apply.
Sometimes I feel so proud to be British.
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Originally Posted by BOBBLEHAT
erm. . . we're not talking about ATSOCAS.
I was simply pointing out that in the UK we can have aircraft outside CAS that are effectively receiving a service that is equivalent to control. And if two such aircraft get close enough together that wake turbulence spacing is an issue then, as far as I'm aware (and I haven't gone looking in the books so I stand to be corrected), WT spacing should be applied.
So yes, aircraft operating outside CAS and not receiving a RAS (or whatever it's called this week), can fly 2 cm away from each other. But if they are under a RAS then the controller should do the approprate thing wrt WT spacing if necessary.
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I just needed a username...i didn't create it to state my position, I wasn't pretending to be something I'm not, If I did I wouldn't be asking questions would I? I hadn't used the forum before so wasn't aware it was such an issue...and 'Greg'...was Taken, unfortunately! I hope I have put your mind at ease...I will change it!!
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OK Greg.. Well from my point of view it did cause confusion. I wondered why an ATCO in the UK would ask such questions. My "name" comes from the fact that I used it as a radio callsign for most of my working life.
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Ok, well I'm sorry for the confusion...I have changed it to - Here2BroadenHorizon - Hopefully that doesn't cause confusion and will let you guys understand why I ask such questions, and just for the record, your question was a bit smart and patronising and I didn't appreciate it.
