4 miles here, 5 miles there - Wake turbulence spacing in different countries
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Ohcirrej
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From: This is the internet FFS.........
4 miles here, 5 miles there - Wake turbulence spacing in different countries
A little instance last night at work where a 757 decided to try and prove it can still fly while flying slower than the cars on the highway below.....with an Airbus on the visual behind got me thinking about the difference in wake turbulence separation requirements in different countries.
Here in Canada, A320 behind 757 requires 5 miles. Over in the UK, 4 miles. Here, PA31 behind 747, 6 miles. Uk requirement, 8 miles. Same PA31 behind A320 in Canada, 4 miles. UK requirements, 6 miles. And this is all before we even get into the "SMALL" category
I find the differences a little amusing, tis all.
Here in Canada, A320 behind 757 requires 5 miles. Over in the UK, 4 miles. Here, PA31 behind 747, 6 miles. Uk requirement, 8 miles. Same PA31 behind A320 in Canada, 4 miles. UK requirements, 6 miles. And this is all before we even get into the "SMALL" category
I find the differences a little amusing, tis all.
Joined: Sep 2000
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From: Toronto
Mr J, the long winter nights must just fly by...
I agree though, it is odd. Maybe the air in different parts of the world causes differences in wake turbulence dissipation.
Whenever we in the tower are about to receive an aircraft with less than the required spacing, the second aircraft miraculously becomes "visual" and all is well again! C208 2 miles behind a heavy, issued a cautionary but still flies on or even below the glide.
I agree though, it is odd. Maybe the air in different parts of the world causes differences in wake turbulence dissipation.
Whenever we in the tower are about to receive an aircraft with less than the required spacing, the second aircraft miraculously becomes "visual" and all is well again! C208 2 miles behind a heavy, issued a cautionary but still flies on or even below the glide.
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From: LHR/EGLL
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From: Enroute.....?
Approach spacing in SA is 8nm behind a heavy and 5 miles behind a medium. Yet a tower controller can squeeze in a VFR trainer 2 miles behind the heavy. Go figure.
I've always wondered if our heavies are heavier than yours....?
I've always wondered if our heavies are heavier than yours....?
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From: South of the Watford Gap, East of Portland
Wake vortices can kill, I and every pilot knows that but....it strikes me, as an airframe operator, that the ATC world does exercise its collective angst and concern about vortex spacing more than crew. I recall reading that there's a review on spacing going on at the moment which might come up with more realistic and practical spacing.
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From: Belgium
). Oh, Mediums don't always like to go 5 NM ( 4.8 in your case ) behind a Heavy either...
Ok, I'll shut up now...
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From: Hongkers
Just want to drag this one to the top again and ask for more info from ATCOs in different parts.
How does your ANSP treat the application of the laid down wake turbulence minima? To simplify things a bit, I'm talking specifically about final spacing in IMC conditions in a radar environment.
How rigidly must it be applied? i.e. is it as strict as radar sep or are you allowed some leeway? If so, what is the a mandatory cutoff? 1/2 mile under? No limit as long as you pass traffic and the pilot is happy to continue? What rationale is used to justify such a reduction?
Look forward to your responses.
How does your ANSP treat the application of the laid down wake turbulence minima? To simplify things a bit, I'm talking specifically about final spacing in IMC conditions in a radar environment.
How rigidly must it be applied? i.e. is it as strict as radar sep or are you allowed some leeway? If so, what is the a mandatory cutoff? 1/2 mile under? No limit as long as you pass traffic and the pilot is happy to continue? What rationale is used to justify such a reduction?
Look forward to your responses.
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From: EBSL / EDYY
Upper Area all is 5NM except Heavy behind a Heavy then it is 6NM. However the seperation minima remains 5NM. Mind you sometimes had complaints about wake turbulence when trailing behind as much as +/- 12NM.
Thread Starter
Ohcirrej
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From: This is the internet FFS.........
How rigidly must it be applied? i.e. is it as strict as radar sep or are you allowed some leeway?
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From: Hongkers
Jerricho
Thanks for the reply.
OK, that sounds like a nice "official" line but at the operational level, what does your Check controller/Stream Manager/Team Leader expect you to do if , for example, the separation between a Heavy and a following Medium erodes to 4.8 NM on late final in IMC? Are you obliged to send the Medium around? How rigidly is that policed in your organization?
Thanks for the reply.
OK, that sounds like a nice "official" line but at the operational level, what does your Check controller/Stream Manager/Team Leader expect you to do if , for example, the separation between a Heavy and a following Medium erodes to 4.8 NM on late final in IMC? Are you obliged to send the Medium around? How rigidly is that policed in your organization?
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From: Hongkers
P.S. Jerricho. I gather from other posts that you are a former UK controller and would therefore be aware of NATS policy regarding the application of the standard. Its not quite as clear-cut as your last post wold indicate.
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From: Golden Road to Samarkand
KiloKilo,
I had the same experience on shift a few years ago. A Medium turbo-prop 18NM behind a B767 on a high speed descent through his level. The turbo-prop reported encountering "Severe Wake Turbulence" and ever since then I've past a caution whenever I thought that a smaller aircraft was going to transit the wake turbulence of a heavy, even if the distance between the aircraft was in excess of the Wake Turbulence Separation Standard behind.
Interesting that on one occasion when I did this, one of my colleagues turned to me and said... "you don't know your Wake Turbulence Standards" because I'd chosen to pass a caution when the distance between the aircraft was in excess of the Wake Turbulence Standard in MATS.
I thought we were in the business of saving people's lives, regardless, but not in spite of, what is written in the books.
I had the same experience on shift a few years ago. A Medium turbo-prop 18NM behind a B767 on a high speed descent through his level. The turbo-prop reported encountering "Severe Wake Turbulence" and ever since then I've past a caution whenever I thought that a smaller aircraft was going to transit the wake turbulence of a heavy, even if the distance between the aircraft was in excess of the Wake Turbulence Separation Standard behind.
Interesting that on one occasion when I did this, one of my colleagues turned to me and said... "you don't know your Wake Turbulence Standards" because I'd chosen to pass a caution when the distance between the aircraft was in excess of the Wake Turbulence Standard in MATS.
I thought we were in the business of saving people's lives, regardless, but not in spite of, what is written in the books.