Separation worry near Bordeaux?

[Doors to Automatic]

I was on a UK bound airliner this afternoon over South-West France.

As we passed to the East of Bordeaux heading in a roughly northerly direction an A320 whizzed past us going south-west at a range which I have never experienced before in over 800 flights as a passenger.

I am fully aware that aircraft may appear closer than they actually are, particularly from a passenger's perspective but I am convinced that the spearation was far less than the 1000 feet and 5 miles which I understand is the minimum.

I could read the airline name and see the tail and type clearly as it passed at a range which I would estimate to be no more than a mile from us (probably less) and maybe 300-400 feet above us.

Can someone reassure me (sensible responses only please as I do know what I am talking about when it comes to these sorts of matters) that we did not experience a near miss and that the separation was sufficient.

We didn't make any deviations off our flight path and I am sure that our crew both saw the other plane (it was clear) and had it on TCAS - it just looked WAY closer than anything I have ever seen before.

Thanks in advance for all sensible responses.

[Bagheera]

Whilst not being able to tell you for certain that you didnt experience a loss of seperation I would suggest that the fact you did not discern any tcas manoeuvre to avoid makes it sound unlikely.
I think it is always particularly difficult for people not used to it to judge the 1,000 ft vertical seperation, use of the word thousand makes it sound like a large distance but it is not. The best way to imagine it using everyday experience is to imagine a motorway junction. Before reaching the turn off you have the blue and white countdown markers (300m,200m,100m). From the 300m marker to the turn off is roughly 1000ft. Now imagine a 747 at the 300m board and an A380 at the turn off and Im sure youll agree you could easily make out the markings on each aircraft.
Alternatively just think Usain Bolt can run that distance in less than 30 Seconds!

[ATCO1969]

"..was far less than the 1000 feet and 5 miles which I understand is the minimum.."

That may be your problem right there, it's either/or, not and.

I've had pilots query whether converging traffic is 1000' above or below, there's no way that SLF would be able to accurately judge while sitting in the back.

DtA, with all respect, members of the public believing that "they know what they are talking about" simply adds to what is a very stressful environment. I was on the desk once when an irate SLF called in to complain that they had to go around because of a firetruck on the runway. After investigation, it emerged that the pilot elected to go around because of an unstable approach off a visual, the firetruck was waiting at the hold to do an inspection!

'69

[10W]

Bagheera has a good description of the distance.

If you're not metric, the aircraft is about 1/5 of a mile vertically from you. Not very far at all.

[eastern wiseguy]

DTA I have no idea whether or not you experienced something untoward. All I can say is that whenever I go on familiarisation flights I am left with the overwhelming feeling that 1000 feet looks awfully close when you are sitting in a jump seat and I have been on many such flights.

Glad you are here to talk about it though.:ok:

[Lon More]

All the above, plus, if the aircraft was in a turn it often seems that an other aircraft may be flying alongside you 300 yards away. In fact it's the required 1000 feet vertical separation.

[Spitoon]

Like others, I cannot tell you whether separation was lost between the aircraft you were travelling on and another but I would point out that there are situations (admitedly not a huge number) where visual separation can be used. The 5 miles/1000 ft separation is a minimum in some situations, but there are many other legitimate separations that might result in aircraft being a lot closer together - completely safely, I might add.

[Doors to Automatic]

Thanks for the replies everyone. I am going on vertical separation rather than the 5 miles and it did seem a lot closer than 1000 ft above us although it is possible that this was an illusion due to its speed.

ATCO1969 - I made that comment to dissuade anyone tempted into making sarcastic comments just because I am an SLF and not a pilot! I would for example know the difference between a runway, taxiway and apron and the position of a fire truck therein :)

[mad_jock]

Doors the first time you get put in a hold after getting that elusive first job as a pilot is a bloody eye opener.

Mine was in Manchester in the Rosun hold in an icle 19 seat turboprop with a heavy two engined jet above us and I had similar feelings to yourself. We didn't have TCAS in them days either so you couldn't see what the seperation was. You knew when it went over head as well because it was if someone turn the lights out.

[chevvron]

I believe airspace in this area is class C in which case ATC could have passed traffic info and let the pilots apply their own separation; I did it myself with 2 x DC 8s at FL350 years ago although admittedly they were both going in the same direction.

[10W]

I believe airspace in this area is class C in which case ATC could have passed traffic info and let the pilots apply their own separation;

Only if both were VFR. For airliners at cruising levels, this is unlikely, more likely to be IFR which requires standard separation.

[millerman]

DtA

Why do you need reassurance? You are still here to ask the question, there was no unnecessary deviation/sudden maneuver which caused pain/panic.
If someone said yes it definitely was a loss of separation - what would you gain? :ok:

[Plazbot]

I think there is no question that you were just seconds from disaster. Infact, it sounds like perhaps the pilots or controllers were conspiring to kill you on purpose! It could be nothing else!

[Doors to Automatic]

DtA

Why do you need reassurance? You are still here to ask the question, there was no unnecessary deviation/sudden maneuver which caused pain/panic.
If someone said yes it definitely was a loss of separation - what would you gain?

Because in the 3000+ hours of my life I have spent in the air, mostly by a window I have never seen another aircraft come so close to mine whilst in the cruise.

[BOAC]

D to A - as said, the fact that you felt no manoeuvre should satisfy you. Separation could easily have been as little as 800ft. My last airline had a 737 that was permanently in error by 100', and if the other a/c has the same, you have 800, plus a little inaccuracy here and there.

[ATCO1962]

D to A; have you spent your 3,000 hours next to a window always on the lookout for traffic? If so, you would have seen a lot of "close calls" ie aircraft that look a lot closer than they are.

If it was TCAS mandatory airspace, I can assure you that you'd have felt some sort of deviation as the pilots got out of each others way. I had that experience as a passenger a few years ago over Turkey. I'd just finished my lunch and felt a sudden bit of negative G as the nose went forward. I talked briefly with my wife, pondering if it was a TCAS event and then opened my window screen. As luck would have it, a B737 went sliding by (maybe less than a half mile, but what do I know) and he was on his way up but it was easy to see that the two aircraft had previously been on a "less-than-separated" track.

Therefore, in answer to your question, I can reassure you that separation was maintained and everybody got home safely. QED and end of thread taking up bandwidth:ok:

[BOAC]

Begging your forgiveness, ATCO:cool:, but for D to A - just to add that the allowable altimeter error at that level is +/- 200 feet, so in theory two a/c could pass within 600' of each other and still be 'legal'.

[Doors to Automatic]

BOAC - I did actually wonder what the allowable margins of error were so if 600-700ft is still legal then I guess we were ok. It just looked very close from where I was sitting. Thanks again to you and everyone else for taking the time to reply.

[ZOOKER]

Doors,
loving your work.
It's fairily difficult for (even experienced) "Watchers Of The Skies" to judge aircraft levels.
But, try this: -
1. Buy an Ordnance Survey Landranger Map. Sheet 129, (Nottingham and Loughborough), will do nicely.
2. Draw pencil lines on the extended centre-lines of R/W 27/09 at EGNX.
3. On the centre-lines, find a position about 3.5 nm from the runway threshold.
(1 nm is 1852 metres), so work it out for yourself. Depending on which end of the runway you go for, it's about the location of either the EMW, or EME, (formally known as the 'Charlie Alpha') NDBs.
4. At your chosen location, (if my recollections of the geomorphology of that area are correct), the local ground elevation is fairly similar to the aerodrome elevation at EGNX. (310 feet or thereabouts).
Now, heres the fun bit: -
At that range from touchdown, aircraft on a 3 degree glidepath are about 1000ft above the runway.
(3 nm - 950ft, 4nm - 1250ft, etc).
5. So, from where you will be standing it's easy to see what 1000ft vertical separation actually looks like, and it's not a lot! - It's about twice the height of Blackpool Tower or 4 times the height if the 'Towers' student accommodation block on the campus at Loughborough University. Yes, the grey one with lots of windows, built in the 1960s. (No, not the green thing, that's The Carillon :=).
6. Hopefully, you will have taken a camera with you during this field-work, - Take lots of good photos, with the sun behind you, (i.e. you will be positioned south of the R/W centre-lines).
7. So, finally, for your efforts, reward yourself with a pint of Marston's or Home Ales finest, depending on whether you ended up in Melbourne or East Leake!
SORTED. :ok:

[Doors to Automatic]

Zooker - following on from the comments of everyone here I was thinking about how I could see the same result again last night as I was driving, and I had EXACTLY the same thought as you have suggested. That is uncanny! I think it would also serve to reassure my fellow pasenger who was convinced we had experienced a near miss. Suggestion of a pint afterwards is a great idea too :p

EDIT: I don't even need to buy a copy of the said "Sheet 129" - I have one right here! :ok:

[HEATHROW DIRECTOR]

They're never as close as they look.. ATCOs at Heathrow Tower, when I was there about 100 years ago, were a quiet, unassuming bunch.. never given to any form of exaggeration.. So, when one popped his head through the rest room doors and announced "The next two landers are so tight they've got the same stand number", the assembled multitude moved in an orderly fashion, similar to a football crowd, to the nearest window. The sight of one turning off with the next one touching down was usually greeted with "..could have got one away in that gap", or "Checker doing an inspection then?", or "s'pose they were making room for a towing Jumbo".... and all the usual rhubarb....

Meanwhile, the Air controller, just relieved, was hurtling horizontally through the Approach Room doors bent on shaking the the Final Director warmly by the throat for making his hair go instantly grey...

Oh happy days........

[LEGAL TENDER]

"..could have got one away in that gap",

I reckon quite easily from the parallel runway ;)

[ZOOKER]

HD,
is that why Heathrow Approach is now 70-ish nm WSW of Heathrow Tower? :E
Keep up the great stories. :ok:

[HEATHROW DIRECTOR]

Zooker.. Dead right!! Too many strangulations plays havoc with the EG list!

Take care...

[Lon More]

HD I remember similar situations back before Maastricht UACC existed and we were still operating next to Brussels ACC on the top floor of the terminal building there. A departure EBBR to ELLX (already refused due traffic) calls on the freq. climbing into the Upper Airspace. Planning Controller, Willy Withofs, throws headset in the air and disappears through the adjoining door only to reappear, seconds later with an ACC controller under his arm, and beating him about the head with an FP strip. He then proceeded to smash the poor bloke's head against the (full) strip bay, screaming, "That's why he was refused!!!" The victim was released to wander home and Willy said, "While i'm up, anyone want coffee?" Happy Days; but to stop a repeat the ddoor was boarded up so we had to go down a floor, run the length of the building and go upstairs again. Too much effort so we stuck to verbal abuse.


Thread drift, not a lot of people know it, but one of the crews in the Tower at Zaventem probably had the unique experience of being relieved by helicopter when the building first was openned back in the 1950s and a fire had cut them off. The stairs on the internal stairways were (still are) made of wood.

[HEATHROW DIRECTOR]

Wonderful story Lon.....

[DFC]

On a more serious note everyone should remember that the "separation standards" are not laid down to ensure that for example aircraft pass over each other 1000ft appart.

The separation standards both horizontal and vertical are designed to ensure that aircraft do not collide.

If the vertical standard is that aircraft without the required horizontal separation most be instructed to fly at indicated levels that are different by 1000ft then one can expect that provided they do, taking all the factors into account they will not hit each other. They may come a lot closer than 1000ft however.

The same applies to for example radar separation - if 5 miles is the standard then provided the controller uses their judgement and decides two radar returns / responses are 5nm appart then while the aircraft may be less than 5nm (radar errors etc etc), they will not be so close that they hit.

So perhaps the aircraft did seem a lot closer than xnm and a lot closer than 1000ft above or below. There is a very good posibility that it was. However, you are a perfect witness to the fact that the systemn works and the aircraft did not hit.

Therefore the objective of ATC - prevent collisions was acheived.