Separation of air traffic

Motorist

Hi all,

Was on a flight last week looking out the port window. We were around 30,000 feet (well above clouds) when I saw a plane in the opposite direction pass by. It seemed really close - I could clearly see details on the fuselage - colours and windows, etc. It was around a hundred feet below us and maybe 500 meters away.

Had never seen a plane this close before - would this be normal separation for planes going in opposite directions? (I realise it's probably hard to judge distance at that altitude when there's nothing to put stuff into perspective)

Thanks

A320

It wasn't a hundred feet anyway,I can imagine the TCAS going mental!!
1000ft is the minimum separation vertically,not sure about laterally,someone here will have a better idea!! Yes you are correct its very hard to judge anything at that altitude!!!

Names

Standard separation is 1000ft vertically and/or 5 nm laterally. The exception to this in Irish airspace is 3nm in the Dublin CTA

Irish Steve

Minimum vertical separation is as stated 1000 Ft, at higher levels it used to be 2000 Ft, but modern equipment has made it possible to reduce it, and get more traffic into the same space.

Horizontal separation is usually 5 miles, but if different size aircraft are all following the same track at the same levels, as happens on approach, the separation can be greater, depending on the size of the aircraft, the bigger the size difference, the greater the separation, In the days of Concorde, the separation between it and a light aircraft was at least 8 miles, which on a busy runway can cause havoc with arrival and departure rates:D

Mistakes can and do lead to less on occasions. I was training below Class A airspace in the UK at one time, and a controller at Gatwick supressed all non Gatwick transponder returns on his screen. A little while later, without putting the transponder returns back on, he allowed a BAC 1-11 to position back to Gatwick from Lasham at 2500 Ft, on the base of the Class A, under his control. At the time, we were at 2400 Ft, completely legal, tracking VOR radials as part of IFR training, working a different radar controller. It was a close encounter, which we were only warned about with less than 15 seconds warning, head to head, the 1-11 turned as he passed over the VOR, less than 500 Ft in front of us, and 100 Ft higher. This was pre TCAS, so neither of us got any other warning, and I doubt that the crew of the 1-11 even saw us, but we as sure as h*ll saw him! We didn't need to file the airmiss, the controller we were working filed it to protect himself, as we were completely legal and working according to the rules. To be fair, the Gatwick controller did apologise to the Lasham controller when he was made aware of what had happened. Still a serious pucker making moment though.

Back in the pre TCAS days, where possible, ATC would give opposite direction traffic a warning if there was only 1000 Ft separation, at high levels the closing speed is so fast, it could be very hard to be sure that there was vertical separation, even with advance warning. Now, TCAS takes much of the pucker factor out of those encounters, the aircraft can be seen on the screen a lot sooner, and if TCAS is not happy, it's very good at getting the attention of the crew very rapidly, and it's the only thing that over rides ATC instructions, a TCAS resolution message is acted on, and only then is ATC informed, and often, by that point, the conflict has already been resolved.

Even with TCAS, accidents happen, a DHL cargo aircraft and a Tu154 collided close to the Swiss border a few years back as a result of a combination of mistakes and misunderstandings.

It's becoming clear that in some cases, 1000 Ft vertically is an issue, there have been several incidents over Europe in recent times where an Airbus 380 flying east has left sufficient vortex wake behind it that a smaller aircraft travelling north west 1000 Ft lower has been "significantly upset" when crossing the track of the 380 a few minutes later. It's the combination of the size and the lower level of the smaller aircraft that's causing the problems.

That said, an Airbus 300 had a fatal accident in New York a few years ago as a result of a vortex wake encounter from a preceding 747, and an incorrect operational procedure, which resulted in the separation of the rudder from the fuselage.

What can be spectacular is on a clear day, if travelling to Heathrow in the morning, take a look out of the window when in the Bovingdon hold, and look at how many aircraft you're sharing the sky with, and how close they all appear to be. When getting to the bottom of the stack, and looking up, there can sometimes be another 7 or 8 aircraft all orbiting in close proximity to each other, which makes for some impressive views.

bombs away

Names wrote: »

Standard seperation is 1000ft vertically and/or 5 nm laterally. The exception to this in Irish airspace is 3nm in the Dublin CTA

Separation is 10nm laterally beyond 13deg west due to accuracy of the radar head, or lack thereof

Johnny901

Another exception would be non-radar separation in a Regional Airport Control Zone i.e Knock etc etc.

Su Campu

This photo was taken over Belgium in November. The photographer was on the ground and the use of the telephoto lense makes it look very like a near miss when in fact the bmiBaby is 2,000 feet below the Tu-154. Looks impossible but it's true. Don't trust what your eyes tell you when there is no perspective.

280special

Just an idea, but if you know roughly what time it was and your flight number you could have a look at either flightradar24.com or radarvirtuel.com, Might give you some info on what the other aircraft type was, how far away it was from you, height etc ?

Motorist

280special wrote: »

Just an idea, but if you know roughly what time it was and your flight number you could have a look at either flightradar24.com or radarvirtuel.com, Might give you some info on what the other aircraft type was, how far away it was from you, height etc ?

Does that show previous flights? It was within the last 7 days.

jimbis

Motorist wrote: »

Does that show previous flights? It was within the last 7 days.

casperflights.com does but you need to subscribe to look back on flights more than 2 hours ago. Maybe someone on here has a subscription and will check if you know flight number/times etc..;)

280special

Motorist wrote: »

Does that show previous flights? It was within the last 7 days.

As of today you can go back to the 11th on http://www.flightradar24.com/

and no subscription required !