passenger jet 'formations'
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passenger jet 'formations'
Something that has puzzled me for a while.
I am led to believe that contrails show up within two defined levels of airspace, the first at about 14,000 feet to 18,000 feet; and the second starting at about 22,000 feet. The airspace in between and below I understand is not given to contrail conditions (?). Personally I would have thought once the conditions were right for contrails, there would be the right conditions for contrails up to space itself.
I understand there are corridors that aircraft use, and I am only asking about passenger jets.
During four months I spent on a beach on the East Kent coast, I noticed there was never a time when just one passenger jet would pass over kent heading 'westward' alone. I noticed there were always either between two and five in indian file, or two side by side ( given a couple of miles ahead or behind ), sometimes this would be one showing contrail and another one lower down and no contrail, sometimes three or four within the same airspace, so to speak. Is there a method here?
Given the amount of airspace visible horizon to horizons, I cannot understand why aircraft are appearing in tandem, threes and fours or more just a few miles abreast and astern of each other. Is there a purpose to this? Given there is supposed to be crowded airspace, this does not fit. The aircraft surely would be more evenly spaced out? I appreciate they are heading to different airports.
I first noticed this in 2006, and to this day, I have never seen just one jet passenger aircraft alone. There is always another one nearby. This is never a case of one on that horizon, the other on that horizon. They are always reasonably close by, albeit one with a contrail showing and another not, due to differing flight levels.
Can anyone explain this or is this just a case of, planes converge like buses? I would have thought the jets would be more evenly spaced across the sky coming into England.
I know nothing about this at all, which is obviously coming across; but it does strike me as odd that the aircraft would clump together like this and squashed up within their corridors.
I am led to believe that contrails show up within two defined levels of airspace, the first at about 14,000 feet to 18,000 feet; and the second starting at about 22,000 feet. The airspace in between and below I understand is not given to contrail conditions (?). Personally I would have thought once the conditions were right for contrails, there would be the right conditions for contrails up to space itself.
I understand there are corridors that aircraft use, and I am only asking about passenger jets.
During four months I spent on a beach on the East Kent coast, I noticed there was never a time when just one passenger jet would pass over kent heading 'westward' alone. I noticed there were always either between two and five in indian file, or two side by side ( given a couple of miles ahead or behind ), sometimes this would be one showing contrail and another one lower down and no contrail, sometimes three or four within the same airspace, so to speak. Is there a method here?
Given the amount of airspace visible horizon to horizons, I cannot understand why aircraft are appearing in tandem, threes and fours or more just a few miles abreast and astern of each other. Is there a purpose to this? Given there is supposed to be crowded airspace, this does not fit. The aircraft surely would be more evenly spaced out? I appreciate they are heading to different airports.
I first noticed this in 2006, and to this day, I have never seen just one jet passenger aircraft alone. There is always another one nearby. This is never a case of one on that horizon, the other on that horizon. They are always reasonably close by, albeit one with a contrail showing and another not, due to differing flight levels.
Can anyone explain this or is this just a case of, planes converge like buses? I would have thought the jets would be more evenly spaced across the sky coming into England.
I know nothing about this at all, which is obviously coming across; but it does strike me as odd that the aircraft would clump together like this and squashed up within their corridors.
Warning Toxic!
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You are so mistaken in so many of your assumptions I don't know where to begin....so I won't. All I can say is 'boy, have you picked up some weird impressions!'
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A "contrail" is a trail of vapour [hence "Vapour Trails"] eminated from the exhausts of Aeroplane engines.
Depending on...
a, The time of year,
b, The Temperature,
c, The Air Pressure,
d, The Humidity,
e, The Altitude
f, The "Persistence", of said trails
Sooo, a "Contrail" will show between 26,000ft and 35,000ft.
IF the conditions are "right", a contrail will "Persist"....ie, last a long time [you have probably seen these...Horizon to Horizon], sometimes, they are "Non-persistant" [the Military love these...[Do not ask why?]
Anything below these altitudes are "Pressure" trails...Like the "Battle of Britain" clips, Aerobatics in "Humid" conditions
All I can say is to ignore Rainboe....an I hope that this helps
Depending on...
a, The time of year,
b, The Temperature,
c, The Air Pressure,
d, The Humidity,
e, The Altitude
f, The "Persistence", of said trails
Sooo, a "Contrail" will show between 26,000ft and 35,000ft.
IF the conditions are "right", a contrail will "Persist"....ie, last a long time [you have probably seen these...Horizon to Horizon], sometimes, they are "Non-persistant" [the Military love these...[Do not ask why?]
Anything below these altitudes are "Pressure" trails...Like the "Battle of Britain" clips, Aerobatics in "Humid" conditions
All I can say is to ignore Rainboe....an I hope that this helps
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Chiglet, thank you.
Rainboe, what is the point of replying to state you cannot be bothered to reply? Details, please.
I ask to learn and understand. From Chiglet, I learnt sum'ink.
Rainboe, what is the point of replying to state you cannot be bothered to reply? Details, please.
I ask to learn and understand. From Chiglet, I learnt sum'ink.
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BTW just to clarify, the aircraft are all present at the same time, in the 'clumps'. I am not looking at contrails left over a period of time. Just those with a plane at the front of it.
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1000tintoys - you have made an intelligent observation and so ask a question. The trouble is that the answer is very obvious to most in these forums so I am sorry if some reply reflects this.
Aircraft fly through specific lanes in the sky following radio aids so that is why they follow each other. Air Traffic Control make sure they are separated by a safe distance.
Aircraft fly through specific lanes in the sky following radio aids so that is why they follow each other. Air Traffic Control make sure they are separated by a safe distance.
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So much rubbish in such a short thread.
Chiglet: where do you get your idea about at what height contrails form? Have you never seen wartime footage of the daylight B-17 raids over Germany operating between 15,000 and 25,000 ft?. More up to date, even small turboprops can trail in the right conditions.
Airways bring aircraft together and the East Kent coast is one of the busier areas of the UK with, apart from London area arrivals and departures many of which will not be trailing, a mass of European traffic into and out of other parts of these islands, not to mention traffic from Scandanavia to Spain and the Europe to North America traffic.
I live on the very edge of the Atlantic and can see two very distinct airways leading to ocean entry points. Every day there is a constant procession to/from the ocean plus a number of random routings. Whilst the processions exist there are many times when only one aircraft is visible and many times when the sky is empty.
As I write, the inbound to Europe rush which started here around 04.30 is quietening down and my SBS shows just two aircraft on one airway within 60 miles of my location whereas an hour ago there were around 12.
Winds, routings and the fact that many departure/arrival times are popular for travel dictate that there can be bunching on certain routes at given times.
A wag once said that the purpose of ATC was to crowd aircraft into the narrowest possible corridors, aiming them at VORs in order to create the need for controllers and allow the rest of the vast sky to be free so the noisy bu**ers flying roundels and stars and bars could have room to enjoy themselves.
Chiglet: where do you get your idea about at what height contrails form? Have you never seen wartime footage of the daylight B-17 raids over Germany operating between 15,000 and 25,000 ft?. More up to date, even small turboprops can trail in the right conditions.
Airways bring aircraft together and the East Kent coast is one of the busier areas of the UK with, apart from London area arrivals and departures many of which will not be trailing, a mass of European traffic into and out of other parts of these islands, not to mention traffic from Scandanavia to Spain and the Europe to North America traffic.
I live on the very edge of the Atlantic and can see two very distinct airways leading to ocean entry points. Every day there is a constant procession to/from the ocean plus a number of random routings. Whilst the processions exist there are many times when only one aircraft is visible and many times when the sky is empty.
As I write, the inbound to Europe rush which started here around 04.30 is quietening down and my SBS shows just two aircraft on one airway within 60 miles of my location whereas an hour ago there were around 12.
Winds, routings and the fact that many departure/arrival times are popular for travel dictate that there can be bunching on certain routes at given times.
A wag once said that the purpose of ATC was to crowd aircraft into the narrowest possible corridors, aiming them at VORs in order to create the need for controllers and allow the rest of the vast sky to be free so the noisy bu**ers flying roundels and stars and bars could have room to enjoy themselves.
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Thanks philbky and albert square. The fact the aircraft are 'clumped' still seems an oddity when I would have thought a longer spread would be safer and therefore less pressure on airports they respectively travel to.
As mentioned, it is very busy in these parts, so perhaps during the day I see bottlenecks of sorts.
Thanks for the posts!
As mentioned, it is very busy in these parts, so perhaps during the day I see bottlenecks of sorts.
Thanks for the posts!
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1000tintoys, type "Free Flight FAA" into Google and have a look at what has been happening (far more slowly than anticipated) in the US where point to point routings selected by pilots, off airways, are being trialled to reduce congestion..
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<<I would have thought a longer spread would be safer >>
Safety is not an issue because those aircraft will be separated by internationally agreed standards. If you increase that separation you incur greater delays. Also, they won't all be going to the same airport so the pressure on the destination airport(s) would not be necessarily be alleviated by spreading them out.
Safety is not an issue because those aircraft will be separated by internationally agreed standards. If you increase that separation you incur greater delays. Also, they won't all be going to the same airport so the pressure on the destination airport(s) would not be necessarily be alleviated by spreading them out.
1000tintoys
Hey TT,
Your question is reasonable. Ask it on the ATC forum; you'll get answers that are:
A More informed and useful to you, and
B Less arrogant, inappropriate and rude than the likes of Rainboe.
Your question is reasonable. Ask it on the ATC forum; you'll get answers that are:
A More informed and useful to you, and
B Less arrogant, inappropriate and rude than the likes of Rainboe.
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Thanks HD and Grizzled.
G; I thought rainboe probably was ATC. No disrespect to the rest.
But I will try on their site.
BTW, with regards to my being told that there were two areas of contrails, ( explanations have been made on this thread now ), the person who told me this said air space had levels just like the depths of the seas had. But I will leave it there and post on ATC.
Thanks to all
G; I thought rainboe probably was ATC. No disrespect to the rest.
But I will try on their site.
BTW, with regards to my being told that there were two areas of contrails, ( explanations have been made on this thread now ), the person who told me this said air space had levels just like the depths of the seas had. But I will leave it there and post on ATC.
Thanks to all
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Chiglet: where do you get your idea about at what height contrails form?
Have you never seen wartime footage of the daylight B-17 raids over Germany operating between 15,000 and 25,000 ft?.
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Agreed contrails are a very complex subject and their formation and dispersal depends on a range of variables.
I've seen them in winter formed briefly as low as 9,000 feet in very cold, saturated, air.
As to the bomber streams, the B17s could reach 35,000 ft, due to the superchargers but on the bigger raids they were streamed at a variety of levels and the trails (as you say possibly due to the superchargers) were just as much in evidence lower down as at higher levels.
In the early 1960s when the 707 and DC8 were the obvious aircraft to look for on the front of trails, the odd DC6 or Connie could be seen with a very short trail.. The oddest thing I ever saw at the front of a long trail in summer was a Shorts Belfast over Lancashire in 1969 slowly drawing a line in the sky which must have been all of 60 miles long - and at FL230!
I've seen them in winter formed briefly as low as 9,000 feet in very cold, saturated, air.
As to the bomber streams, the B17s could reach 35,000 ft, due to the superchargers but on the bigger raids they were streamed at a variety of levels and the trails (as you say possibly due to the superchargers) were just as much in evidence lower down as at higher levels.
In the early 1960s when the 707 and DC8 were the obvious aircraft to look for on the front of trails, the odd DC6 or Connie could be seen with a very short trail.. The oddest thing I ever saw at the front of a long trail in summer was a Shorts Belfast over Lancashire in 1969 slowly drawing a line in the sky which must have been all of 60 miles long - and at FL230!
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contrails are a very complex subject and their formation and dispersal depends on a range of variables
Seem to remember that the altitutes for the formation of contrails could be worked out from the good old Tephigram. Have long forgotten how to do it though.
