How to manufacture a Mid-Air.
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Capt Windsock, I have to disagree with your (perhaps flippant?) comment, (“ offsetting is great as long as you are the only aircraft doing it. ” posted 16 June 2001 15:20 )
The fact is, the safety margin doubles if all opposite direction traffic offsets one mile right; ie, if the navigation equipment is accurate (and the indisputable fact is, it is - very, very accurate), the separation between opposite direction traffic becomes 2 NM, because each aircraft is 1NM right of the airway centreline.
[This message has been edited by 410 (edited 18 June 2001).]
The fact is, the safety margin doubles if all opposite direction traffic offsets one mile right; ie, if the navigation equipment is accurate (and the indisputable fact is, it is - very, very accurate), the separation between opposite direction traffic becomes 2 NM, because each aircraft is 1NM right of the airway centreline.
[This message has been edited by 410 (edited 18 June 2001).]
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A cynical hypothesis on the "30- mile lateral" vs 1,000' RVSM- (I believe) there are ususally 5 NAT tracks, identified A-E so if you reduce separation laterally to 1/2 a degree of latitude you would add an extra 4 tracks. By introducing RVSM between FLs 290 & 430 you add 7 FLs, or 7 new "tracks" (or have I got the vertical dimensions for RVSM embarrassingly wrong?).
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In the airprox incident that prompted this whole thread it was stated that clear air turbulance caused the aircraft being overtaken to climb through the RVSM levels. It also appears that very smart Eurocontrol people are talking about domestic RVSM. What will happen even at FL300+ when clear air turbulance or predictable mountain waves etc cause these kinds of conditions in greatly more congensted airspace than over the middle of the Atlantic or Pacific? Seems that offsets or some other method of allowing for this type of sudden climb or descent would be a necessary condition to provide a safety margin.
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We started this offset topic more than two years ago on this forum and on Avweb. The articles posted were from us here in Singapore and some friends in Dubai. Our topic was posted under the name" FLY RIGHT" and I wonder if it is still on the server. I am happy to see that it is a current topic again and perhaps we can get some things moving on this subject.
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I don't have an axe to grind on RVSM -- I wish I flew something that got up to those levels. But I'm somewhat surprised to see this incident used to support the anti-RVSM case.
The incident revolves around the unexpected climb of the A340 after a turbulence encounter while the vertical separation between the aircraft was 1000 ft.
It strikes me that:
1) The turbulence encounter could easily have occured at the lower levels where the standard separation is and has always been 1000 ft.
2) In this case the A340 climbed 2400 ft before descending again. If no lateral separation had existed and the vertical separation had been 2000 ft, the aircraft would still have collided.
I was particularly surprised by the following comment.
There didn't seem to be a great deal of evidence that an aircraft at FL380 would have been able to react in time either.
By contrast, the incident seems to demonstrate that lateral separation of tracks under all circumstances is a sensible precuation.
Or am I missing the point of the anti-RVSM case?
The incident revolves around the unexpected climb of the A340 after a turbulence encounter while the vertical separation between the aircraft was 1000 ft.
It strikes me that:
1) The turbulence encounter could easily have occured at the lower levels where the standard separation is and has always been 1000 ft.
2) In this case the A340 climbed 2400 ft before descending again. If no lateral separation had existed and the vertical separation had been 2000 ft, the aircraft would still have collided.
I was particularly surprised by the following comment.
<font face="Verdana, Arial, Helvetica" size="2">Such was the vigour of the A340's climb in AoA law, the aircraft could well have climbed through FL 363 (thus provoking a TCAS RA with revised software version 7.0) in a very short time, even if the crew had applied nose-down sidestick as soon as they heard the (delayed) autopilot disconnect warning. The climb to FL 363 would have been sufficient to generate a TCAS RA in any adjacent aircraft at FL 370 but, if the intruder aircraft continues its climb, there can be no guarantee that an aircraft directly above it could respond in sufficient time to avoid a collision. Therefore, the RVSM safety case should not be driven by any assumption that a different crew might have contained the situation by making an earlier nose-down sidestick command than the A340 crew involved in this incident.</font>
By contrast, the incident seems to demonstrate that lateral separation of tracks under all circumstances is a sensible precuation.
Or am I missing the point of the anti-RVSM case?
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Bookworm--
Would totally agree. However, the powers that be have decided that RVSM is here to stay, inspite of any problems. Afraid it will take "bent metal" before anything is done, due to a very big loss of face syndrome otherwise. Lateral spacing IMHO is much better.
Was there/is there a problem with Airbus aircraft that would indicate this is unique to the A330/340?
Would totally agree. However, the powers that be have decided that RVSM is here to stay, inspite of any problems. Afraid it will take "bent metal" before anything is done, due to a very big loss of face syndrome otherwise. Lateral spacing IMHO is much better.
Was there/is there a problem with Airbus aircraft that would indicate this is unique to the A330/340?
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<font face="Verdana, Arial, Helvetica" size="2">Was there/is there a problem with Airbus aircraft that would indicate this is unique to the A330/340?</font>
It could be argued that the crew should have made a nose-down sidestick input much earlier, but that's easy to say with the benefit of hindsight. It could perhaps be argued that the "AoA protection law" is of limited value in the cruise at FL360.
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Sorry, got to close this thread until 'forget' fixes their email as all the notification of replies are bouncing to me.
As and when I recieve notification that the email address has been fixed I will re-open the thread.
------------------
Capt PPRuNe
aka Danny Fyne
The Professional Pilots RUmour NEtwork
As and when I recieve notification that the email address has been fixed I will re-open the thread.
------------------
Capt PPRuNe
aka Danny Fyne
The Professional Pilots RUmour NEtwork
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It's a real pity to see such an important topic slide off the top page.
I hope the day never arives when some senior ICAO official or airline manager finds himself facing some high-powered lawyer who asks him why ICAO or the airline had never though this issue important enough to acton, given that at least one fatal accident involving large passenger jets, the USAF/GAF midair off the west coast of Africa some years ago, might have been avoided if offset tracking was mandatory.
Someone has said it before in earlier threads - the sad fact is, fare-paying Western passengers, probably lots of them, will have to die before anything is done.
I hope the day never arives when some senior ICAO official or airline manager finds himself facing some high-powered lawyer who asks him why ICAO or the airline had never though this issue important enough to acton, given that at least one fatal accident involving large passenger jets, the USAF/GAF midair off the west coast of Africa some years ago, might have been avoided if offset tracking was mandatory.
Someone has said it before in earlier threads - the sad fact is, fare-paying Western passengers, probably lots of them, will have to die before anything is done.
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Just a few remarks after several years of oceanic and other flying.
Oddly enough, the only other case I have recent knowledge of was an own company A330, over the Atlantic, which had an altitude excursion following,"the worst turbulence the captain had ever experienced".
Oceanic traffic goes in swarms in the same direction with only occasional opposite traffic. If everyone offset it would achieve nothing.
In high density Europe under RVSM it would be reassuring to see the oppos slide down the other side. You have to be there with a joint speed of 1,000 mph to appreciate how little time you have to react to a potential conflict.
With regard to reducing lateral separation on the Atlantic by 50%, consider this: communication is still by antiquated HF via radio operators, not ATC controllers.
On a bad day you may take 20 minutes to make contact with the guy and possibly never get a response to a request to deviate off track due to severe weather.
By then you have probably had to take the initiative to take whatever avoiding action is required.
With reduced lateral separation it would just make that, officially, unauthorised deviation more risky.
You don't have to spend much time over the Ocean to reallise how little actual control there is in the continental sense.
I believe the general public would be amazed.
Oddly enough, the only other case I have recent knowledge of was an own company A330, over the Atlantic, which had an altitude excursion following,"the worst turbulence the captain had ever experienced".
Oceanic traffic goes in swarms in the same direction with only occasional opposite traffic. If everyone offset it would achieve nothing.
In high density Europe under RVSM it would be reassuring to see the oppos slide down the other side. You have to be there with a joint speed of 1,000 mph to appreciate how little time you have to react to a potential conflict.
With regard to reducing lateral separation on the Atlantic by 50%, consider this: communication is still by antiquated HF via radio operators, not ATC controllers.
On a bad day you may take 20 minutes to make contact with the guy and possibly never get a response to a request to deviate off track due to severe weather.
By then you have probably had to take the initiative to take whatever avoiding action is required.
With reduced lateral separation it would just make that, officially, unauthorised deviation more risky.
You don't have to spend much time over the Ocean to reallise how little actual control there is in the continental sense.
I believe the general public would be amazed.
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How many more “Close Calls”
The attached file is a copy of an article that appeared in last week’s USA Today. It describes another near miss over Indian Airspace and casually mentions in it’s closing paragraph that there had been some 20 near collisions in Indian skies since November 1996.
Now it doesn’t need an Einstein to realize that one of these days it won’t be a near miss but a full hit.
With “Freeflight” and the implementation of full Fans still a decade away, are we just going to sit and wait for a disaster to happen. The Airway system and communication system over India (and many more places in the world for that matter) are completely outdated and not capable of handling today’s traffic volume. A friend of mine, who is a leading design engineer in navigation equipment, told me that he sometimes had sleepless nights realizing that the equipment designed today was so accurate that, used in the present ATC environment, would one day contribute to a midair.
We cannot sit idle and wait for some beancounting bureaucrat in organizations like ICAO and JAA to change and adapt ATC procedures to create a safer environment, and avoid such disasters from happening. We all know that changes will not come soon, and only after several disasters will somebody wake up and actually start to do something.
I believe, and have argued this before, that we should start a discussion to come up with some ideas and/or procedures as to how to implement the legal and authorized changes in the present system. With the many aviation forums that we have today,let us use these forums to encourage positive discussions, resulting in policy changes, and increased safety.
For the time being, Offset Tracking is an individual choice, to increase separation, and is being used by more an more pilots (as per several articles in Flight International). But as long as these procedures remain someone’s individual technique, it might and will work for that crewmember, but is not used to it’s full effect as it is not an official procedure.
Offset Tracking, Parallel-Oneway airways, direct INS and GPS routes are all procedures that can be implemented fairly easily and without great financial inputs. Why is it not happening, and what are the political forces stopping it from happening?
Where do we start, and what is the procedure to follow?
The irony of the situation is that, while we are flying a multi-million dollar piece of equipment into the 21st century, screaming at the top of our voices over some outdated piece of HF equipment, trying with 100 other flyers to get our position known to an Indian ATC controller, you can step back into our luxurious passenger cabins, where every passenger today can swipe his creditcard through his individual armrest satellite phone and have immediate 5/5 duplex phone connection with anybody in the world.
I wonder if we have got our priorities right.
The attached file is a copy of an article that appeared in last week’s USA Today. It describes another near miss over Indian Airspace and casually mentions in it’s closing paragraph that there had been some 20 near collisions in Indian skies since November 1996.
Now it doesn’t need an Einstein to realize that one of these days it won’t be a near miss but a full hit.
With “Freeflight” and the implementation of full Fans still a decade away, are we just going to sit and wait for a disaster to happen. The Airway system and communication system over India (and many more places in the world for that matter) are completely outdated and not capable of handling today’s traffic volume. A friend of mine, who is a leading design engineer in navigation equipment, told me that he sometimes had sleepless nights realizing that the equipment designed today was so accurate that, used in the present ATC environment, would one day contribute to a midair.
We cannot sit idle and wait for some beancounting bureaucrat in organizations like ICAO and JAA to change and adapt ATC procedures to create a safer environment, and avoid such disasters from happening. We all know that changes will not come soon, and only after several disasters will somebody wake up and actually start to do something.
I believe, and have argued this before, that we should start a discussion to come up with some ideas and/or procedures as to how to implement the legal and authorized changes in the present system. With the many aviation forums that we have today,let us use these forums to encourage positive discussions, resulting in policy changes, and increased safety.
For the time being, Offset Tracking is an individual choice, to increase separation, and is being used by more an more pilots (as per several articles in Flight International). But as long as these procedures remain someone’s individual technique, it might and will work for that crewmember, but is not used to it’s full effect as it is not an official procedure.
Offset Tracking, Parallel-Oneway airways, direct INS and GPS routes are all procedures that can be implemented fairly easily and without great financial inputs. Why is it not happening, and what are the political forces stopping it from happening?
Where do we start, and what is the procedure to follow?
The irony of the situation is that, while we are flying a multi-million dollar piece of equipment into the 21st century, screaming at the top of our voices over some outdated piece of HF equipment, trying with 100 other flyers to get our position known to an Indian ATC controller, you can step back into our luxurious passenger cabins, where every passenger today can swipe his creditcard through his individual armrest satellite phone and have immediate 5/5 duplex phone connection with anybody in the world.
I wonder if we have got our priorities right.
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People - a lot of people - have already died when opposite direction traffic has collided using the same airway. (See the Pprune Home page for details from 1996.) This was one of Pprune's earliest 'crusades', and unfortunately, little or nothing has been achieved since then except a few more line pilots have been made aware of the problem.
Let's be clear about one thing: more people are going to die in midairs unless we as an industry do something about fixing this all too easily fixed problem. It's not good enough for isolated individuals to fly offset. Everyone with the super accurate GPS/INS should do it, and the only way that will ever happen is if the equipment does it automatically.
Every time in the past this has been raised, someone chimes in 'proving' it won't work because of one thing or another. It's all too easy to be dragged off on a tangent with arguments like this. The RVSM camp see their problem, the NATS track people theirs, ATC people see the call for offsetting as an affront or criticism of their professionalism, the mathematicians can 'prove' it makes the risk of collision more likely.
Let's agree that the problem offsetting is attempting to address applies in no way, shape or form with NATS tracks, which have problems unique to the busy (and usually one way at different times of day) traffic patterns North Atlantic. I'm mainly concerned with the non-radar environment outside Western Europe and the US. And I'm not slagging off the controllers in these other parts of the world. It's just that it's a fact of life they are forced to work in a far from ideal environment with sometimes poor or outdated equipment, bad (and sometimes no) comms with neighbouring agencies because of political conflicts. Anyone with any imagination can see the potential for serious traffic conflict in such environments because of the high accuracy of modern navigation systems. The only long term answer is unidirectional airways, but I wouldn't hold my breath waiting for them.
What amazes me is the concerted resistance that people in authority (and therefore not flying the line daily) are maintaining to addressing this navigation accuracy problem. It will probably take at the very least some embarrassing disclosures by some 'muck raking' journalist to shake these agencies into doing something. (Thanks to sites like this, they won't be able to say they or the industry as a whole were unaware the problem existed.) Unfortunately, it's unlikely any such journalist will see any news value in any such story until a lot of people have died in circumstances that cannot be disguised as being attributable to anything but the accuracy of the nav systems. Let's hope that's a long time (if never) coming, but I fear that's a faint hope.
Let's be clear about one thing: more people are going to die in midairs unless we as an industry do something about fixing this all too easily fixed problem. It's not good enough for isolated individuals to fly offset. Everyone with the super accurate GPS/INS should do it, and the only way that will ever happen is if the equipment does it automatically.
Every time in the past this has been raised, someone chimes in 'proving' it won't work because of one thing or another. It's all too easy to be dragged off on a tangent with arguments like this. The RVSM camp see their problem, the NATS track people theirs, ATC people see the call for offsetting as an affront or criticism of their professionalism, the mathematicians can 'prove' it makes the risk of collision more likely.
Let's agree that the problem offsetting is attempting to address applies in no way, shape or form with NATS tracks, which have problems unique to the busy (and usually one way at different times of day) traffic patterns North Atlantic. I'm mainly concerned with the non-radar environment outside Western Europe and the US. And I'm not slagging off the controllers in these other parts of the world. It's just that it's a fact of life they are forced to work in a far from ideal environment with sometimes poor or outdated equipment, bad (and sometimes no) comms with neighbouring agencies because of political conflicts. Anyone with any imagination can see the potential for serious traffic conflict in such environments because of the high accuracy of modern navigation systems. The only long term answer is unidirectional airways, but I wouldn't hold my breath waiting for them.
What amazes me is the concerted resistance that people in authority (and therefore not flying the line daily) are maintaining to addressing this navigation accuracy problem. It will probably take at the very least some embarrassing disclosures by some 'muck raking' journalist to shake these agencies into doing something. (Thanks to sites like this, they won't be able to say they or the industry as a whole were unaware the problem existed.) Unfortunately, it's unlikely any such journalist will see any news value in any such story until a lot of people have died in circumstances that cannot be disguised as being attributable to anything but the accuracy of the nav systems. Let's hope that's a long time (if never) coming, but I fear that's a faint hope.
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As a start, talk to your Chief Pilot / Fleet Manager and ask for it to be tabled at the next Standards meeting for discussion, Farside.
It probably won't get up on the first try, but keep reminding those above how important you think it is.
It probably won't get up on the first try, but keep reminding those above how important you think it is.
Blacksheep: I don't know about the CAA over there, but our head people at the DOT and FAA etc are always White House appointees, and usually consist of lawyers and/or career politicians. One guy at the FAA had been a Thunderbird pilot but he was just another personal ticket-puncher.
What the FAA might not be taking into account when they perform their 'cost/benefit' analyses is the ever-growing trend to outsource any and all major aircraft maintenance.
JetBlue sends many, if not most of their A-320s each year to El Salvador for C or D checks. Even in the US, also according to the same article in either "the New York Times" or "the Wall Street Journal", as a minimum, only the maintenance supervisor is required to have an FAA license! Even before our oldest fleet was equipped with the RVSM alimeters etc, many of our planes returned from a place (not too far north of the very white sand) and were grounded for a while. They almost lost their license to do the work, until a company Maint. Crew Chief was based down there (this he told us upon arrival from ATL).
Is any of this already the case with European airlines? About the only US major to perform most of the technical work in-house is American Airlines, and they have never yet filed for Chapter 11. Well-done American!
What the FAA might not be taking into account when they perform their 'cost/benefit' analyses is the ever-growing trend to outsource any and all major aircraft maintenance.
JetBlue sends many, if not most of their A-320s each year to El Salvador for C or D checks. Even in the US, also according to the same article in either "the New York Times" or "the Wall Street Journal", as a minimum, only the maintenance supervisor is required to have an FAA license! Even before our oldest fleet was equipped with the RVSM alimeters etc, many of our planes returned from a place (not too far north of the very white sand) and were grounded for a while. They almost lost their license to do the work, until a company Maint. Crew Chief was based down there (this he told us upon arrival from ATL).
Is any of this already the case with European airlines? About the only US major to perform most of the technical work in-house is American Airlines, and they have never yet filed for Chapter 11. Well-done American!
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willadvise is taking his Air Traffic Control paradigm too literally.
There are things that ATC cannot control - turbulence, Comm and/or Xpdr loss, a host of other systems & environment anomolies. When this happens ATC has only minutes to provide separation info to other flights, and when this secondary level of protection is less than perfect, a tertiary level (ie offset) can save the day.
There are things that ATC cannot control - turbulence, Comm and/or Xpdr loss, a host of other systems & environment anomolies. When this happens ATC has only minutes to provide separation info to other flights, and when this secondary level of protection is less than perfect, a tertiary level (ie offset) can save the day.
