Another very close ORD near hit.
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SAO, I understand how that might work, but Tree's a/c was on base, not downwind. Of course, with your scenario you then have the issue of the separation between the one joining 09L from left downwind, and the one that is already established behind it on 09R.
Now I'm confused, if you're going to vector to final, even when using visuals, what's the benefit?
You'll find that at airports that use visual approaches effectively, vectoring to final is always given to ensure efficient spacing.
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Ok, one more attempt. I originally entered this discussion with a plan to explain some of the differences between European and North American procedures/practices/real world operations and to counter the unfair criticism of ORD. That is the benefit of the forum that I value.
For those of you who wish to take posts literally.
Gonzo: 1. I meant and should have said "more frequent go-arounds than LHR"
2. Visualize it as a slinky toy, if there is a gap the coils behind it will fill it via increasing speed or shortening turn to final etc, I have not heard a European approach controller request/allow an increase in speed but in NA it is routine to fill the "gap". Please understand that this is not a single/dual parallel landing runway operation with strict runway limited volumes. There are multiple choices and flexibility at ORD.
Say Again, Over!
Thank you for your professional input, I am not doing very well at explaining this from a pilot's perspective.
May I say it is one of those "you had to be there" discussions.
For those of you who wish to take posts literally.
Gonzo: 1. I meant and should have said "more frequent go-arounds than LHR"
2. Visualize it as a slinky toy, if there is a gap the coils behind it will fill it via increasing speed or shortening turn to final etc, I have not heard a European approach controller request/allow an increase in speed but in NA it is routine to fill the "gap". Please understand that this is not a single/dual parallel landing runway operation with strict runway limited volumes. There are multiple choices and flexibility at ORD.
Say Again, Over!
Thank you for your professional input, I am not doing very well at explaining this from a pilot's perspective.
May I say it is one of those "you had to be there" discussions.
Last edited by Tree; 19th Jan 2007 at 03:54.
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Will you permit a couple of questions from a mere SLF to help me understand this better?
In LAHSO ops, am I to understand that the tower will clear an a/c to take off before an a/c landing on a conflicting runway has stopped short but in anticipation that it will? If that's correct, then I can see the risks. But if the tower will not clear take off until the landing a/c has actually actually stopped short, then I can't see what the problem is - can someone clarify?
Also, if you're approaching an airport where they conduct LAHSO ops but your company doesn't permit it and you say "I can't accept LAHSO" what happens next? Are you effectively saying "You have cleared me to land but do NOT clear anyone to t/o on a conflicting runway"? If so, is that not also horrendously risky in case the tower forgets that you're not going to LAHSO?
Sorry if I've completely misunderstood all this and am wasting your time.
Thanks in advance, M63
In LAHSO ops, am I to understand that the tower will clear an a/c to take off before an a/c landing on a conflicting runway has stopped short but in anticipation that it will? If that's correct, then I can see the risks. But if the tower will not clear take off until the landing a/c has actually actually stopped short, then I can't see what the problem is - can someone clarify?
Also, if you're approaching an airport where they conduct LAHSO ops but your company doesn't permit it and you say "I can't accept LAHSO" what happens next? Are you effectively saying "You have cleared me to land but do NOT clear anyone to t/o on a conflicting runway"? If so, is that not also horrendously risky in case the tower forgets that you're not going to LAHSO?
Sorry if I've completely misunderstood all this and am wasting your time.
Thanks in advance, M63
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Midland63:
Try this link and go to 4.4.9; 4.3 and below to LAHSO.
http://www.tc.gc.ca/CivilAviation/pu.../4-1.htm#4-4-9
This is the Canuck version. The FAA version is similar. It requires training/knowledge/certification in the Airline's OPS Manuals. I don't know of any Canadian operators who are certified to use it in the USA. Canadian operators use it in Canada.
Try this link and go to 4.4.9; 4.3 and below to LAHSO.
http://www.tc.gc.ca/CivilAviation/pu.../4-1.htm#4-4-9
This is the Canuck version. The FAA version is similar. It requires training/knowledge/certification in the Airline's OPS Manuals. I don't know of any Canadian operators who are certified to use it in the USA. Canadian operators use it in Canada.
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Gonzo,
I know it sounds weird to vector an aircraft to final on a visual approach but allow me an explanation.
In Canada, an aircraft on an ILS approach has to intercept the LOC 2 miles from the GP intercept so it often means a turn at 9 to 10 miles final.
Now picture a situation with two aircraft that will be at the 10 mile final point at the same time, one straight-in, the other from a downwind leg to a base etc. If the one on downwind leg sees the airport, notwithstanding noise abbatement, he can be turned on a nice tight base leg (4 or 5 miles) and with a few artfull speed adjustments
on the second aircraft, you just gained a slot since the number 2 essentially disappeared.
Then, let me go back to the 09R/09L example. On parallel runways that are too close together to permit independant ops, I would have to keep vertical separation until both aircraft are established. Now let's consider IMC operations with a 10 mile altitude of 3000. Let's consider further that the LOC to 09L is packed with arrivals 3 miles apart. To use 09L, I have to keep vertical sep with all traffic on 09R, therefore intercept final at 4000 (provided parallel traffic on 09R is at 3000 or 5000) which means I can't turn in until 12 or 13 miles final.
Now: All of a sudden, the weather clears and the aircraft on the downwind to 09L sees the airport and all appropriate trafic on 09R LOC. I can then tell him to "turn base now, cleared visual approach 09L". Or: "Turn left heading 120 to intercept final, maintain visual separation from xxxxx on 09R, cleared visual approach 09L".
Hope that makes sense.
Midland63,
SIRO / LAHSO is a bit of a controversial issue, I'll have to confess. I completely agree with the concerns pilots have in its use and in less than ideal conditions, it can and will pose a safety hazard.
Let me just state the way I use it. I work CYYZ tower for 5 years and we were trained to "not set up a weld". Here's what I mean: As an example, let's use runways 05 and 33R, which intersect about 3/4 of the way down each runway. To better describe it, if an aircraft was to roll out on 05 and find itself unable to stop short of 33R, 3/4 of the way down, it could have a very close look at an aircraft about to rotate on 33R, 3/4 of the way down.
Now, about the weld. I was trained to never issue a take-off clearance to an aircraft on 33R when the lander on 05 was overflying the threshold since they would, should something go wrong, meet and weld. This obviously has to be tempered with type of aircraft landing and taking off. A DH8 on 05, vs another DH8 on 33R. We'd do it all day. Heavy to heavy, NO WAY!
I now work approach control for two airport that use SIRO / LAHSO and my personnal philosphy is that I never set anything that would see two aircraft at the intersection at the same time. I'll go tighter than what normal runway sep standards would allow (we can discuss this later if you want) but leave myself 1/2 a mile one way or the other.
Hope that helps,
LX
CYOW & CYQB Approach
I know it sounds weird to vector an aircraft to final on a visual approach but allow me an explanation.
In Canada, an aircraft on an ILS approach has to intercept the LOC 2 miles from the GP intercept so it often means a turn at 9 to 10 miles final.
Now picture a situation with two aircraft that will be at the 10 mile final point at the same time, one straight-in, the other from a downwind leg to a base etc. If the one on downwind leg sees the airport, notwithstanding noise abbatement, he can be turned on a nice tight base leg (4 or 5 miles) and with a few artfull speed adjustments
on the second aircraft, you just gained a slot since the number 2 essentially disappeared.Then, let me go back to the 09R/09L example. On parallel runways that are too close together to permit independant ops, I would have to keep vertical separation until both aircraft are established. Now let's consider IMC operations with a 10 mile altitude of 3000. Let's consider further that the LOC to 09L is packed with arrivals 3 miles apart. To use 09L, I have to keep vertical sep with all traffic on 09R, therefore intercept final at 4000 (provided parallel traffic on 09R is at 3000 or 5000) which means I can't turn in until 12 or 13 miles final.
Now: All of a sudden, the weather clears and the aircraft on the downwind to 09L sees the airport and all appropriate trafic on 09R LOC. I can then tell him to "turn base now, cleared visual approach 09L". Or: "Turn left heading 120 to intercept final, maintain visual separation from xxxxx on 09R, cleared visual approach 09L".
Hope that makes sense.
Midland63,
SIRO / LAHSO is a bit of a controversial issue, I'll have to confess. I completely agree with the concerns pilots have in its use and in less than ideal conditions, it can and will pose a safety hazard.
Let me just state the way I use it. I work CYYZ tower for 5 years and we were trained to "not set up a weld"
. Here's what I mean: As an example, let's use runways 05 and 33R, which intersect about 3/4 of the way down each runway. To better describe it, if an aircraft was to roll out on 05 and find itself unable to stop short of 33R, 3/4 of the way down, it could have a very close look at an aircraft about to rotate on 33R, 3/4 of the way down.Now, about the weld. I was trained to never issue a take-off clearance to an aircraft on 33R when the lander on 05 was overflying the threshold since they would, should something go wrong, meet and weld. This obviously has to be tempered with type of aircraft landing and taking off. A DH8 on 05, vs another DH8 on 33R. We'd do it all day. Heavy to heavy, NO WAY!
I now work approach control for two airport that use SIRO / LAHSO and my personnal philosphy is that I never set anything that would see two aircraft at the intersection at the same time. I'll go tighter than what normal runway sep standards would allow (we can discuss this later if you want) but leave myself 1/2 a mile one way or the other.
Hope that helps,
LX
CYOW & CYQB Approach
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Midland63,
I forgot to answer the second part of your question. Oops...
Yes, that is indeed what you are saying and we'll be happy to oblige. We expect to hear you say it on initial contact with approach though and not on short final as we're about to issue t/o clearance.
In a situation where 2 aircraft are coming in to land and LAHSO is needed for both to land, if one was to neglect to tell us on first contact and only mention it when 2 or 3 miles final, BACK UP HE GOES! He should have said so on farther out so the approach controller could set it up differently.
As far as the danger of us forgeting is concerned, don't worry. Part of the landing/take-off clearance includes either the hold short instruction and traffic information or traffic information about the other aircraft holding short. Therefore, the pilot would be "forced" to remind us he can't/won't do LAHSO and we would go to plan "B".
Cheers,
LX
I forgot to answer the second part of your question. Oops...
In a situation where 2 aircraft are coming in to land and LAHSO is needed for both to land, if one was to neglect to tell us on first contact and only mention it when 2 or 3 miles final, BACK UP HE GOES! He should have said so on farther out so the approach controller could set it up differently.
As far as the danger of us forgeting is concerned, don't worry. Part of the landing/take-off clearance includes either the hold short instruction and traffic information or traffic information about the other aircraft holding short. Therefore, the pilot would be "forced" to remind us he can't/won't do LAHSO and we would go to plan "B".
Cheers,
LX
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SAO,
Sorry, when you said 'vectoring to final' I thought you meant you'd give radar vectors to the final approach: I can certainly understand vectoring to a position where the a/c can accept a visual from base/late downwind.
I understand all the rest too, but my point was this: You have a line of inbounds on the 09R ILS, 3 miles apart. Aircraft A is now on a visual left base to 09L. You give traffic and tell it to maintain own sep against aircraft B in 09R ILS. Aircraft C is 2.5 miles behind B also on the 09R ILS, which still needs standard separation, and since he's been on an ILS approach, with heads down.
I appreciate the increase in landing rate that manoeuvre would provide, and at airports where noise abatement, outbound delay, ground configuration and other such considerations allow, it would obviously be beneficial.
Tree,
Same as you, although I've recently encountered a great deal of criticism of our (Heathrow's) 'lack of flexibility' from some US pilots. We all work to different regulations/noise procedures/layout constraints etc. I was attempting to show that we all do our best according to what we get given to work with.
LHR approach regularly keep a/c at a high(er) speed down the approach to facilitate closing a gap. However, we don't have many occasions (other than the very rare lack of traffic), to cause such gaps on approach. Indeed, on westerly ops we are dictated to by noise procedures that we are only permitted to use one of our runways for landing, except in an emergency or urgent situation.
Sorry, when you said 'vectoring to final' I thought you meant you'd give radar vectors to the final approach: I can certainly understand vectoring to a position where the a/c can accept a visual from base/late downwind.
I understand all the rest too, but my point was this: You have a line of inbounds on the 09R ILS, 3 miles apart. Aircraft A is now on a visual left base to 09L. You give traffic and tell it to maintain own sep against aircraft B in 09R ILS. Aircraft C is 2.5 miles behind B also on the 09R ILS, which still needs standard separation, and since he's been on an ILS approach, with heads down.
I appreciate the increase in landing rate that manoeuvre would provide, and at airports where noise abatement, outbound delay, ground configuration and other such considerations allow, it would obviously be beneficial.
Tree,
Same as you, although I've recently encountered a great deal of criticism of our (Heathrow's) 'lack of flexibility' from some US pilots. We all work to different regulations/noise procedures/layout constraints etc. I was attempting to show that we all do our best according to what we get given to work with.
LHR approach regularly keep a/c at a high(er) speed down the approach to facilitate closing a gap. However, we don't have many occasions (other than the very rare lack of traffic), to cause such gaps on approach. Indeed, on westerly ops we are dictated to by noise procedures that we are only permitted to use one of our runways for landing, except in an emergency or urgent situation.
ALPA has advised it's members not to accept LAHSO. A lot of US carriers have followed this advice and have told their crews not to accept.
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GWH,
Nothing specific, just remarks that if LHR was in the US, it would move a lot more traffic.
I asked for more details, and things like allowing a lot more more visual approaches, using both runways in mixed mode and simultaneous parallel approaches were mentioned.
Nothing specific, just remarks that if LHR was in the US, it would move a lot more traffic.
I asked for more details, and things like allowing a lot more more visual approaches, using both runways in mixed mode and simultaneous parallel approaches were mentioned.
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Don't worry Gonzo,
It seems as if you can never move enough traffic sometimes. Both LOCs could be full for 30 miles with an aircraft taking-off in every 2.5NM gap and still, "somebody somewhere" could do it so much better. 
Cheers,
LX
It seems as if you can never move enough traffic sometimes. Both LOCs could be full for 30 miles with an aircraft taking-off in every 2.5NM gap and still, "somebody somewhere" could do it so much better.
Cheers,
LX
Last edited by Say Again, Over!; 24th Jan 2007 at 11:27. Reason: Oopsies in spelling!
