Near miss over The Hammers???
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Originally Posted by PPRuNe Radar
Professor Yaffler
You are welcome to post here and the ATC bunch are normally never shy at coming forward to explain things (but the truth might be less shocking than portrayed in the guter press
)
The minimum distance confirmed by radar recordings was 1000' vertical separation. Absolutely normal in a holding pattern
and in most other parts of the sky.
NATS has equipment called Separation Monitoring Function which continually measures the vertical and horizontal distances between aircraft at all times. It is independent of the ATC controllers suites and will give an alert to the Supervisor if the parameters are breached. These parameters are smaller than the proscribed separation standards since there is some accuracy leeway, particularly in level occupancy by pilots, and numerous false alerts would ensue if it went off at the separation minima. The figure you calculate (565 feet) would fall within these parameters and if that had been the true vertical separation (and the aircraft were within a minimum horizontal separation parameter), then the controllers involved would have been filling in forms and having chats without tea and biscuits. You simply can't not notice an Air Prox event since Big Brother won't let you. And nor will the pilots who monitor their TCAS.
As was pointed out to the press by those in the know when quizzed at the time, there was no incident, because separation was provided as per the standards. No sensionalism can hype up the fact that it was a simple everyday event with no loss of any safety standards. Although some have tried to to sell their rags by trying to make it appear as a near catastrophe
You are welcome to post here and the ATC bunch are normally never shy at coming forward to explain things (but the truth might be less shocking than portrayed in the guter press
)The minimum distance confirmed by radar recordings was 1000' vertical separation. Absolutely normal in a holding pattern
and in most other parts of the sky.NATS has equipment called Separation Monitoring Function which continually measures the vertical and horizontal distances between aircraft at all times. It is independent of the ATC controllers suites and will give an alert to the Supervisor if the parameters are breached. These parameters are smaller than the proscribed separation standards since there is some accuracy leeway, particularly in level occupancy by pilots, and numerous false alerts would ensue if it went off at the separation minima. The figure you calculate (565 feet) would fall within these parameters and if that had been the true vertical separation (and the aircraft were within a minimum horizontal separation parameter), then the controllers involved would have been filling in forms and having chats without tea and biscuits. You simply can't not notice an Air Prox event since Big Brother won't let you. And nor will the pilots who monitor their TCAS.
As was pointed out to the press by those in the know when quizzed at the time, there was no incident, because separation was provided as per the standards. No sensionalism can hype up the fact that it was a simple everyday event with no loss of any safety standards. Although some have tried to to sell their rags by trying to make it appear as a near catastrophe
Any way, Just think of the jobs it would create.
Now where are my slide rule and log tables.
I'm Just A Lawnmower
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Of course, they could be quite legally closer together than the much quoted 1000ft, given mode C tolerance. The DHL 767 could have been at FL92 with the JAL 777 at FL98, only 600ft apart. Indeed, the JAL could have been procedurally cleared to FL100 after the DHL had reported leaving it, dropped like a stone and reached 100 well before the DHL reached 90. Ooer!
Right, what is the Sunday Mirror's phone number
Right, what is the Sunday Mirror's phone number
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At last! Has Balix perhaps finally solved this geometric and emotional conundrum? He wrote: "Of course, they could be quite legally closer together than the much quoted 1000ft, given mode C tolerance. The DHL 767 could have been at FL92 with the JAL 777 at FL98, only 600ft apart."
This figure of 600 feet is close to the euclidian calculations of ProfYaffler and others, but is also presumably just outside the range at which the Separation Monitoring Function sounds its bells or whatever before automatically writing the relevant resignation letters for the guilty parties to sign.
But think what this means: those much maligned journalists who reported that the aircraft appeared to be closer together than the published separation figure of 1000 feet might actually have been right! If so, I wonder if those posters who were so quick to pour emotional scorn on the journalistic race will be as rapid with their apologies?
This figure of 600 feet is close to the euclidian calculations of ProfYaffler and others, but is also presumably just outside the range at which the Separation Monitoring Function sounds its bells or whatever before automatically writing the relevant resignation letters for the guilty parties to sign.
But think what this means: those much maligned journalists who reported that the aircraft appeared to be closer together than the published separation figure of 1000 feet might actually have been right! If so, I wonder if those posters who were so quick to pour emotional scorn on the journalistic race will be as rapid with their apologies?
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SMF wouldn't have triggered as it works off the radar data - which quite clearly shows FL100 and FL090 (and 0.3nm laterally at the CPA). I've replayed the data and checked. You'll to trust me on that as, although I could post a screenshot of the replay, I'm not going to do that on a public forum with what's probably NATS proprietary data.
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Hi Guys,
It is amazing what a camera can do! Out of curiosity, would this scenario have shown on the TCAS so the pilots were aware of where each other were?
Also, does anyone have a link to the picture mentioned on page 1 concerning a 747 and a 757?
Captain McDuff
It is amazing what a camera can do! Out of curiosity, would this scenario have shown on the TCAS so the pilots were aware of where each other were?
Also, does anyone have a link to the picture mentioned on page 1 concerning a 747 and a 757?
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There could, quite rightly, have only been 600ft separation between the two aircraft. But the replays clearly shows that there was 1000ft. Plus, anyone that is in the business knows that TCAS would be acting in this situation if they really were close, and not trying to get the DHL perfectly in formation beind the JAL!!!! I'm kind of getting the feeling though, that a lot of people wish they were closer. Why is that???!
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<<If so, I wonder if those posters who were so quick to pour emotional scorn on the journalistic race will be as rapid with their apologies?>>
I don't think so, Seloco. Pilots, controllers and other aviation professionals have had to put up with far too much garbage from journos over the years; it just gets too tiresome.
Why anyone is even bothering to argue about how close they might have been I can't imagine. The radar playback says they were 1000ft apart. End of story. A thousand aeroplanes a day will be similarly separated over London. Are people going to argue that they all might be separated by only 600ft... C'mon..
I don't think so, Seloco. Pilots, controllers and other aviation professionals have had to put up with far too much garbage from journos over the years; it just gets too tiresome.
Why anyone is even bothering to argue about how close they might have been I can't imagine. The radar playback says they were 1000ft apart. End of story. A thousand aeroplanes a day will be similarly separated over London. Are people going to argue that they all might be separated by only 600ft... C'mon..
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Sadly HD you are right, but then every profession has to put up with inaccurate and sensationalist journalistic reporting - t'is the way of the world. There are however many extremely good journalists who work hard to understand the topic on which they are writing, and are keen to get the right answers to the questions on aspects of that topic which they do not fully understand. They are unlikely to even ask these questions if the first reaction from professionals to that which they have had the temerity to write is to be described as the spawn of the devil, or worse!
The story in this case was actually rather simple, wasn't it: standard separation is 1000 feet; allowable tolerances can safely reduce this to 600 feet before warnings sound and systems kick in; holding patterns mean that several aircraft can be in the same vista of sky at the same time; viewed from 10000 feet below (with or without a telephoto lens) that can look, to a layman, extremely close. But, it is OK and always has been and the West Ham turf, old peoples homes and primary schools have all survived another day.
The story in this case was actually rather simple, wasn't it: standard separation is 1000 feet; allowable tolerances can safely reduce this to 600 feet before warnings sound and systems kick in; holding patterns mean that several aircraft can be in the same vista of sky at the same time; viewed from 10000 feet below (with or without a telephoto lens) that can look, to a layman, extremely close. But, it is OK and always has been and the West Ham turf, old peoples homes and primary schools have all survived another day.
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Just a thought about the mode-c tolerance.
The tolerance is for difference between the reported altitude (i.e that showing on the altimeter in the cockpit) and the altitude shown on radar.
If there was an error and the altimeter is showing FL90 then the mode -c would be between FL88 and FL92 (to be within tolerances
Conversley - if there was an error and it is between tolerances - if the Mode C is showing FL90 then the altimeter will be showing FL88-FL92 - Implying the pilot has levelled at a level inconsitent with his clearance.
The tolerance is for difference between the reported altitude (i.e that showing on the altimeter in the cockpit) and the altitude shown on radar.
If there was an error and the altimeter is showing FL90 then the mode -c would be between FL88 and FL92 (to be within tolerances
Conversley - if there was an error and it is between tolerances - if the Mode C is showing FL90 then the altimeter will be showing FL88-FL92 - Implying the pilot has levelled at a level inconsitent with his clearance.
By the way: today I had a truly terrifying experience! There I was, quietly enjoying the view from my train window, travelling at a comfortable speed of about a hundred MPH, when all of a sudden hell broke loose: a high-speed train approached us head on, missing us only by mere inches! 
The terror-stricken faces of the passengers in the other train were clearly visible; they are burned in my memory forever.
Of course the railways deny any wrongdoing, using their usual cover-up tactics. Well, they'll never see me on their trains again!
The terror-stricken faces of the passengers in the other train were clearly visible; they are burned in my memory forever.
Of course the railways deny any wrongdoing, using their usual cover-up tactics. Well, they'll never see me on their trains again!
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xetroV.. Phewww, I know exactly what you mean. Sounds as if, thankfully, the driver, 35-yr old Fred Smith, with his scarf blowing back in the wind, was able to steer the train away from a disaster at the last moment thereby also missing a children's playground and the local old people's home... What a hero!
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Its a fair cop guv.
Originally Posted by YourFriendlyATCO!
There could, quite rightly, have only been 600ft separation between the two aircraft. But the replays clearly shows that there was 1000ft. Plus, anyone that is in the business knows that TCAS would be acting in this situation if they really were close, and not trying to get the DHL perfectly in formation beind the JAL!!!! I'm kind of getting the feeling though, that a lot of people wish they were closer. Why is that???!
Now where did I make a mistake...(reaches for slide rule...)
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ProfessorY;
There have been several other threads on this site which have talked about this (now) infamous photograph.
I am sure you know this as you have posted on some of them!
You even started one - 'closed threads'. On that thread, before it was closed(!!) I posted 2 photographs to show how the camera deceives the eye. The link to the thread is below, mine is the second to last post, showing 2 photographs of a plant in a driveway, with a house behind. The plant was not moved between taking the photographs.
http://www.pprune.org/forums/showthread.php?t=208834
What I think you will find is that most people here are not hacked off at the ignorance of Joe Public, but more p***ed off at the blatant cynicism of the photographer who sold a photograph using sensationalism as his bargaining chip, when he knew full well why his photograph looked like it did.... foreshortening by zoom lenses is a basic fundamental fact in photography and lots of keen amateur photographers with a decent SLR and ALL professional photographers know about it.
The copy editor of the 'newspaper' (in the loosest terms) would also either be aware of it or would have talked to people on his staff who would be in the know, when he checked out the story.
There are losses of separation almost every day, be it due to controller error, pilot error, or equipment malfunction. Every one of these is investigated and logged. There are no cover ups; our industry is all too aware of the implications of screwing up, therefore we have an open reporting system, whereby we can learn from incidents that other people have, to try to make us aware of possible problems etc.
To any Moderator who must be bored by now, reading yet another thread about this non subject - any chance of going for a record amount of closures and doing the honour with this one??
There have been several other threads on this site which have talked about this (now) infamous photograph.
I am sure you know this as you have posted on some of them!
You even started one - 'closed threads'. On that thread, before it was closed(!!) I posted 2 photographs to show how the camera deceives the eye. The link to the thread is below, mine is the second to last post, showing 2 photographs of a plant in a driveway, with a house behind. The plant was not moved between taking the photographs.
http://www.pprune.org/forums/showthread.php?t=208834
What I think you will find is that most people here are not hacked off at the ignorance of Joe Public, but more p***ed off at the blatant cynicism of the photographer who sold a photograph using sensationalism as his bargaining chip, when he knew full well why his photograph looked like it did.... foreshortening by zoom lenses is a basic fundamental fact in photography and lots of keen amateur photographers with a decent SLR and ALL professional photographers know about it.
The copy editor of the 'newspaper' (in the loosest terms) would also either be aware of it or would have talked to people on his staff who would be in the know, when he checked out the story.
There are losses of separation almost every day, be it due to controller error, pilot error, or equipment malfunction. Every one of these is investigated and logged. There are no cover ups; our industry is all too aware of the implications of screwing up, therefore we have an open reporting system, whereby we can learn from incidents that other people have, to try to make us aware of possible problems etc.
To any Moderator who must be bored by now, reading yet another thread about this non subject - any chance of going for a record amount of closures and doing the honour with this one??
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Sorry UKATCO_535 but you are missing the point by patronising ProfY. Of course he, and many others on this thread, knows how a telephoto lens can appear to distort distances between objects - many of us are photographers too! What the Prof was trying to do was to show, by simple geometry (and it is really straightforward maths..) what the "infamous" series of photographs were ACTUALLY showing, rather than what they APPEARED to show. Inconveniently, ProfY's geometric analysis came up with a result that was at odds with what we are told the ATC tapes showed. The Prof was keen to understand why; that seems reasonable to me.
Incidentally exactly the same relative-scale analysis can be carried out on your two flower pot pictures; it proves of course that the distance between them and the far flower bed is the same.
Incidentally exactly the same relative-scale analysis can be carried out on your two flower pot pictures; it proves of course that the distance between them and the far flower bed is the same.