Aircraft Separation

newdigi

Hi,

I was on a flight a few days ago out of dublin and just off the coast of wexford I noticed an airline coming towards us (was seated on the left hand side of the plane). I've seen aircraft in the vicinity of a plane ive been on countless times but this seemed pretty close.

so i just checked it on FR24 just now and got the following at the point the two aircraft crossed each other:

aircraft I was on:
altitude: 33,900ft
track: 178 deg
latitude: 52.29
longitude: -6.25


other aircraft:
altitude: 35,975 ft
track: 281 deg
latitude: 52.26
longitude: -6.16

So i just got to wondering how much separation does there actually have to be? I've no doubt this was normal as I assume the pilots, aircraft and ATC know exactly whats going on.

This one just got me thinking as it was a large aircraft (turns out it was an A346)

Thanks

urajoke

5nm's or 1000ft but that can be reduced to 3nm's or 1000ft depending on the airspace.

You won't be able to tell how far apart you were by LAT/LONGs.

Tenger

newdigi wrote: »

.......I've seen aircraft in the vicinity of a plane ive been on countless times but this seemed pretty close.

so i just checked it on FR24 just now and got the following at the point the two aircraft crossed each other:

aircraft I was on:
altitude: 33,900ft


other aircraft:
altitude: 35,975 ft

2000ft separation......no bother. As stated above 1000ft is the normal separation.

2 stroke

If I can add my own curiosity to this. When altitude is stated as 35,975 ft, thats quite a precise figure. Is this measured to the bottom, middle or top of the plane? Do all countries, airlines and manufacturers use the same measuring point on the plane?

bkehoe

2 stroke wrote: »

If I can add my own curiosity to this. When altitude is stated as 35,975 ft, thats quite a precise figure. Is this measured to the bottom, middle or top of the plane? Do all countries, airlines and manufacturers use the same measuring point on the plane?

The static ports are normally half way up the fuselage on any aircraft I've seen.

However, the FR24 'altitudes' are actually the flight level reported by the transponder of the aircraft which is the altitude measured from a standard atmospheric datum of 1013 hectopascals and is not necessarily the true altitude of the aircraft above sea level.

iusedtoknow

I was a flight recently, and a plane seemed very close to us - we were a 747 and the other plane was a easyjet looked to be climbing out from Manchester - the pilot even came on and said that "it was entirely normal what just happened"....it got me thinking that it probably wasn't, if the pilot was on the intercom about it . It was BA so he was very calm and british about it.

I actually love when you approach heathrow at a busy time and you are put in a pattern (actually..when isn't a busy time at LHR) and the pilots will usually say that "you'll see planes closer than usual, it's entirely expected"

newdigi

thanks for the replies. it did seem quite close but was obviously normal. was a lovely flight overall due to the amount of sky traffic i got to see

amen

urajoke wrote: »

5nm's or 1000ft but that can be reduced to 3nm's or 1000ft depending on the airspace.

You won't be able to tell how far apart you were by LAT/LONGs.

Why not ? I make it about 7kms apart

urajoke

amen wrote: »

Why not ? I make it about 7kms apart

I should have said accurately.

folbotcar

The limits are exactly as urajoke stated. That can seem quite close when dealing with big aircraft. On long haul flights passing aircraft seem to rocket past just below you. Very impressive with closing speeds near a thousand miles an hour. :eek::eek:

Although my most impressive moment was seeing a Ryanair 737 pass below me while I putt putted along in a Cessna 150 at 5000 feet over County Meath. It wasn't a near miss or anything like that. We were both aware of each other.

galwayjohn89

folbotcar wrote: »

Although my most impressive moment was seeing a Ryanair 737 pass below me while I putt putted along in a Cessna 150 at 5000 feet over County Meath. It wasn't a near miss or anything like that. We were both aware of each other.

That be brilliant, hopefully that will happen to me sometime. Still remember taxing a C150 near a B747 in Sanford. I felt like an ant.

folbotcar

Vuzuggu wrote: »

That be brilliant, hopefully that will happen to me sometime. Still remember taxing a C150 near a B747 in Sanford. I felt like an ant.

It doesn't have to be a 747. I was lined up waiting at Dublin when a DC9 taxied up behind me, I mean right behind me. I felt an ant with an anteater about to strike. :eek: ATC took the hint and moved me out of the way.

CaptainSkidmark

Some random FYI, Choppers going to rigs fly at 3000 feet and return at 1500 feet!