What is the regulation spacing of airlines when flying?
Discussion
When airlines are flying in the air, what should be the separation distance in any given direction?
And if a passenger feels like they have seen a near-miss can they themselves report it anywhere?
Two cases here:
Myself; a flight from Fuzhou to Shanghai (Chinese internal flight), I was looking out of the window and 'whoooooosh' I see another plane flying parallel and at exact same altitude in the oppposite direction that looked to be only 500m away. I get a proper shock and think shyyyte that was close.
My work colleague today tells me that he saw a plane on his flight to Toulouse in France at the weekend come very close. He was looking out of the window and 'whoosh' a plane flying NOT PARALLEL but at the same altitude flies across their line of flight. He presumes the distance to be about 500m or less.
The worrying thing here is that I'd guess a second difference here or there would mean the planes would have been occupying the exact same piece of air.
And if a passenger feels like they have seen a near-miss can they themselves report it anywhere?
Two cases here:
Myself; a flight from Fuzhou to Shanghai (Chinese internal flight), I was looking out of the window and 'whoooooosh' I see another plane flying parallel and at exact same altitude in the oppposite direction that looked to be only 500m away. I get a proper shock and think shyyyte that was close.
My work colleague today tells me that he saw a plane on his flight to Toulouse in France at the weekend come very close. He was looking out of the window and 'whoosh' a plane flying NOT PARALLEL but at the same altitude flies across their line of flight. He presumes the distance to be about 500m or less.
The worrying thing here is that I'd guess a second difference here or there would mean the planes would have been occupying the exact same piece of air.
king caps lock.It's very easy to think the other plane is closer than it actually is.
I've flown from LHR to NCL in the cockpit jumpseat (pre 9/11 obviously) and planes that were miles and miles away were setting off warnings for the pilots so nothing to worry about. I'd imagine you're more likely to hit another plane on the ground, which happened to us in Antigu on the way to St Lucia.
I've flown from LHR to NCL in the cockpit jumpseat (pre 9/11 obviously) and planes that were miles and miles away were setting off warnings for the pilots so nothing to worry about. I'd imagine you're more likely to hit another plane on the ground, which happened to us in Antigu on the way to St Lucia.
The line astern separation is determined by the size of the wing tip vortex of the aircraft in front. At one stage, larger aircraft used to add "Heavy" to their call signes to alert following aircraft that they were big vortex producers. That was in the days when large widebodied airliners were in the minority. Now they make up almost 50% of all airliners in use so they don't tend to use this technique any more.
The answer is really that it depends upon many factors.
Certain airspace areas have different separation minima defined by the radar or lack off in the region. Vertical separation used to be 2,000ft vertically above FL290 due to limitations in older pressure altimeters.
Most of Europe, USA and some other parts of the world are now RVSM (reduced vertical separation minima) areas where vertical separation is 1,000ft as long as the aircraft are 'RVSM equiped' and have the right altimetery and transponders on board.
Horizontal separation varies hugely and also really depends upon where you are in the world and even the class of airspace in that area. In some areas it is based simply on time between aircraft on the same airway In others it is distance from crossing traffic. I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
Take off separation is limited by the wake turbulence category of the departing aircraft and the one following it.
Certain airspace areas have different separation minima defined by the radar or lack off in the region. Vertical separation used to be 2,000ft vertically above FL290 due to limitations in older pressure altimeters.
Most of Europe, USA and some other parts of the world are now RVSM (reduced vertical separation minima) areas where vertical separation is 1,000ft as long as the aircraft are 'RVSM equiped' and have the right altimetery and transponders on board.
Horizontal separation varies hugely and also really depends upon where you are in the world and even the class of airspace in that area. In some areas it is based simply on time between aircraft on the same airway In others it is distance from crossing traffic. I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
Take off separation is limited by the wake turbulence category of the departing aircraft and the one following it.
Edited by el stovey on Monday 6th July 11:42
el stovey said:
The
I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
Well I know for sure that the plane I saw was no where near 5nm or even 3nm separation.I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
I know that planes can seem closer than they actually are etc. but I could pick out certain fuselage writing and windows quite clearly. And then there was the speed difference.... the combined speed of the plane I was in and the opposing speed of the other plane, .....it was very clearly about 500m or under (in my opinion of course).
Wondering if it is something passengers see on a regular basis and if we are allowed to notify anybody about it?
AJI said:
el stovey said:
The
I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
Well I know for sure that the plane I saw was no where near 5nm or even 3nm separation.I'd expect the minimum distance horizontally to be not less than 5nm but have seen 3nm or less before.
I know that planes can seem closer than they actually are etc. but I could pick out certain fuselage writing and windows quite clearly. And then there was the speed difference.... the combined speed of the plane I was in and the opposing speed of the other plane, .....it was very clearly about 500m or under (in my opinion of course).
Wondering if it is something passengers see on a regular basis and if we are allowed to notify anybody about it?
the aircraft was more than likely 1000ft above or below. It can often seem that another aircraft is at your level. 1000ft isnt really that much.
As said earlier, in RVSM airspace 1000ft is the minimum seperation, so another aircraft can pass directly above/below you.
i wouldnt worry too much to be honest. The transponders fitted on modern airlines (and soon to be all light aircraft) 'talk' to each other. if there is a collision or close call predicted then the pilots of both planes will be told and action will be taken. If it was really 500m or less at the same altitude then i would have definately said corrective action would have been taken (ie, you would have climbed or descended to avoid)
As said earlier, in RVSM airspace 1000ft is the minimum seperation, so another aircraft can pass directly above/below you.
i wouldnt worry too much to be honest. The transponders fitted on modern airlines (and soon to be all light aircraft) 'talk' to each other. if there is a collision or close call predicted then the pilots of both planes will be told and action will be taken. If it was really 500m or less at the same altitude then i would have definately said corrective action would have been taken (ie, you would have climbed or descended to avoid)
Edited by El Capitano on Monday 6th July 13:52
Ive seen this a few times, where I look out the window and swear ive just seen another aircraft buzz by. I do remember one dusky evening looking out of a BA flight to Barbados ond on the port side and just behind were two military jets!
got worried for a bit until they just peeled away after a few seconds.
very weird to see though
got worried for a bit until they just peeled away after a few seconds.
very weird to see though
Edited by Obiwonkeyblokey on Monday 6th July 16:38
The separation minima in the UK are as follows:
Vertical Separation:
Up to FL290 1000ft separation applies.
Above FL290 2000ft separation applies unless aircraft are RVSM equipped, in which case minimum separation is 1000ft.
Horizontal Separation:
Minimum of 5nm between IFR aircraft unless the controlling unit is approved to use 3nm separation (most approach units). Heathrow Director (Final Approach) is authorised to use 2.5nm spacing where no wake turbulence requirement exists.
There are many more separations based on time/distance from beacons and relative tracks of the aircraft, but these are many and varied and will usually guarantee more than the 5nm anyway, so aren't of any interest to your question.
Wake turbulence spacing for approaching aicraft in trail varies hugely depending on the leading and the following aircraft. A Cessna 152 behind a 747 needs 7 miles for example, but behind a 737 it need only 5 miles, and behind a Dash 8 would need only 4 miles.
Reduced Separation
Controllers can apply something called 'reduced separation in the vicinity of an aerodrome' if certain conditions are met. This means that if you have the required visibility to see both aircraft, you can allow them to be closer than 3nm if you can see they are separated from each other. This also applies if the pilots agree they can see each other and maintain their own separation.
Departure Separation
As el stovey said, departure separation is based on vortex requirements, but there is also longitudinal separation that has to be applied if the preceding departure was slow and/or flying the same route as the next departure. If something sluggish launches on a departure route ahead of a jet, it will hold up the jet for around 4 mins usually. Controllers have a set of parameters and timings that give them the required departure spacing as a time.
At busy airports, Ground Control and Tower have to plan ahead to get the best order of departures to reduce delays. You will try to get aircraft on diverging routes to be staggered to allow you the minimum: a one minute split. Grouping aircraft of the same weight category will reduce time between departures also.
There is also the possibility that the aircraft were as close as you thought because someone made a mistake and separation was lost. However, this is fairly rare and would likely have resulted in some sudden climb or descent if the aircraft caused a TCAS alert, as El Capitano has already mentioned.
Vertical Separation:
Up to FL290 1000ft separation applies.
Above FL290 2000ft separation applies unless aircraft are RVSM equipped, in which case minimum separation is 1000ft.
Horizontal Separation:
Minimum of 5nm between IFR aircraft unless the controlling unit is approved to use 3nm separation (most approach units). Heathrow Director (Final Approach) is authorised to use 2.5nm spacing where no wake turbulence requirement exists.
There are many more separations based on time/distance from beacons and relative tracks of the aircraft, but these are many and varied and will usually guarantee more than the 5nm anyway, so aren't of any interest to your question.
Wake turbulence spacing for approaching aicraft in trail varies hugely depending on the leading and the following aircraft. A Cessna 152 behind a 747 needs 7 miles for example, but behind a 737 it need only 5 miles, and behind a Dash 8 would need only 4 miles.
Reduced Separation
Controllers can apply something called 'reduced separation in the vicinity of an aerodrome' if certain conditions are met. This means that if you have the required visibility to see both aircraft, you can allow them to be closer than 3nm if you can see they are separated from each other. This also applies if the pilots agree they can see each other and maintain their own separation.
Departure Separation
As el stovey said, departure separation is based on vortex requirements, but there is also longitudinal separation that has to be applied if the preceding departure was slow and/or flying the same route as the next departure. If something sluggish launches on a departure route ahead of a jet, it will hold up the jet for around 4 mins usually. Controllers have a set of parameters and timings that give them the required departure spacing as a time.
At busy airports, Ground Control and Tower have to plan ahead to get the best order of departures to reduce delays. You will try to get aircraft on diverging routes to be staggered to allow you the minimum: a one minute split. Grouping aircraft of the same weight category will reduce time between departures also.
There is also the possibility that the aircraft were as close as you thought because someone made a mistake and separation was lost. However, this is fairly rare and would likely have resulted in some sudden climb or descent if the aircraft caused a TCAS alert, as El Capitano has already mentioned.
Edited by RDE on Tuesday 7th July 20:42
Hi,
the word "heavy" is still attached to the end of the callsign in the USA, and i think whilst talking with the approach controller in Australia.
The A380 uses "super" rather than heavy after the callsign. Heavy aircraft need 6 miles behind the A380 whilst on the approach to land.
Rgds.
the word "heavy" is still attached to the end of the callsign in the USA, and i think whilst talking with the approach controller in Australia.
The A380 uses "super" rather than heavy after the callsign. Heavy aircraft need 6 miles behind the A380 whilst on the approach to land.
Rgds.
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