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-   -   Airprox over London tonight (Wed)? (https://www.pprune.org/spectators-balcony-spotters-corner/130942-airprox-over-london-tonight-wed.html)

BEagle 20th May 2004 17:46

Warped Factor - no, nothing like a wake vortex encounter. Those are invariably accompanied by an element of buffet and lateral oscillation, nothing like this smooth, positive and obviously well flown steep turn.

Notso Fantastic 20th May 2004 18:37

Oh my word, the idiocy gets worse! Someone trying to pretend that he has seen an 'incident', bank being judged from a view out of the cabin.....whatever next?
IF there was an airprox, it will be official. You cannot, even as a fairly experienced pilot, accurately estimate bank from a cabin window unless you have an across horizon reference. It's not unknown for turboprops to bank more than jets due to their slower speed and hence less 'g', but still naughty- but I defy anybody to put a figure to it!

End of 'incident'?

HEATHROW DIRECTOR 20th May 2004 18:53

<<Both aircraft were at the end of a right turn, seemed to be at very similar altitude and extremely close laterally. I've never seen any so close. Second, faster, aircraft suddenly powered up, dropped right wing and turned very sharply.>>

When I worked at Heathrow ATC I lost count of the number of phone calls I fielded from members of the public and experienced pilots saying just the same thing. I've seen it myself many, many times.

Fact is, from the ground you simply cannot tell. If Heathrow turns an inbound one off Biggin downwind right in front of an outbound 1000 ft below the phone rings quite quickly.

BEagle 20th May 2004 19:22

"It's not unknown for turboprops to bank more than jets due to their slower speed and hence less 'g', but still naughty- but I defy anybody to put a figure to it"

Absolute horsefeathers! For any aeroplane at all, N (or Gz if you prefer) = L/W and is equal to the secant of the angle of bank. The radius of turn is equal to TAS squared divided by the product of the tangent of the angle of bank and g (9.81 m/s/s) - whether in a Cub, Comet or Concorde.

As for estimating AoB - if you have been flying for a few years and are sitting in the back of an ATR with a very good view of the wing/horizon angle, it's reasonably simple to estimate AoB.

InFinRetirement 20th May 2004 19:43

Two points!

Firstly, who on the ground can assess a 1000' seperation from one aircraft above or below another?

Secondly, snide remarks to BEagle are unwarranted - I suggest you read his profile and back off!

Notso Fantastic 20th May 2004 20:00

Granted my point about 'g' was wrong, but turboprops have been known from first hand knowledge to bank more than jets ever do.
I do not agree that even experienced pilots can accurately estimate large bank angles from a window, no matter how 'experienced' they are! A wing and a horizon are not enough.
This whole thread is a fraud started by someone trying to suggest it was a bit more 'official' than a Mk 1 eyeball! Unless anybody can prove an incident actually occured rather than an inexperienced aeroplane watcher seeing what he thinks is an 'incident', then we are wasting bandwidth on a fools errand. As for estimating bank out of a cabin window, it is purely an academic discussion not worthy of wasting any time on.

Codman 20th May 2004 20:38

Notso Fantastic - I've no significant scientific prowess with regard to aerodynamics but having flown turboprops and passengered in them many times I do recall this. When sat in a v narrow tube with a view out of both sides you can most definately detect steeper than usual AoB and they are most disconcerting. Granted, one window and a view of a field is not enough but look across the aisle and it does become apparent.

Jerricho 20th May 2004 20:59

As 2 people here I highly respect and listen to state, it is very, very hard to gauge vertical separation standing on the ground, even when both concerned aircraft are at least 1000 feet apart.

Perhaps you could tell us what runway Heathrow was landing on when you saw this happen.

MaxAOB 20th May 2004 23:13

:O

Notso!!!

A window and a horizon is not enough!!!! Your post beggars belief. How do you think vfr flying is taught. I am sure you are aware of Beagles credentials and if he says it was 40 degrees then it was probably somewhere in the region of 39 -41 degrees! Having flown all manner of light fixed wing, jetstreams, ATR's and now jets for airlines various i can assure you that every ops manual i have read has stipulated that normal turns should not exceed 30 degrees angle of bank. In fact in most airlines if 30 degrees is exceeded the NHP is required to call "bank angle"! Then again maybe you work for Iberia!!



:} :hmm: :ok:

Capn Notarious 20th May 2004 23:48

Now shake hands make up and be friends: the world needs lots.

sread 21st May 2004 01:42

Well, what a can of worms I opened here!
I am sorry if I've offended anyone by asking the question that started all this off. That wasn't my intention.

His dudeness 21st May 2004 07:12

sread,
don^t take it personal.
Point is, as already pointed out, its very hard to tell from the ground, especially if the involved a/c are of different sizes....

Your story reminded me of a flight I did earlier this year, joining the hold over METRO (FRA) there was a Korean 747 just 1000ft below, we looked at him and tried to take digipics, when all of a sudden our passengers unstrapped himself, wen^t up front and told us to: "tell the tower there is a big aeroplane pretty close, a 747, we will crash"....

For the bank angle issue: our KingAir A/P is limited to 25 deg, the citationjet does a max of 30 degs...

eal401 21st May 2004 08:28

My apologies to BEagle, I wasn't aware of his background and did not intend any offence!

BEagle 21st May 2004 10:11

eal401, mate - no offence taken.

And no apology needed. In a multi-pilot environment, if ever you spot something about which you have doubt, raise your opinion. The crusty old git smelling of wee in the other seat is NOT perfect - and the better ones will respect you for having spoken up. If you happen to be wrong, they will explain why, not bite your nose off!

Due to cumulative fatigue (8 free days in 3 months) I once comprehensively porked up a middle of the night approach, despite the other pilot expressing his doubts - we had to go round and circle to land. Too fast, too close because I was knackered and way behind the drag curve and wasn't listening properly. In the debrief, I commended him for his very positive CRM and gave myself a comprehensive ar$e-kicking!

Always raise your doubts if you see something which you're uncertain about!

Notso Fantastic 21st May 2004 16:57

MaxAOB-<A window and a horizon is not enough!!!! Your post beggars belief. How do you think vfr flying is taught. I am sure you are aware of Beagles credentials and if he says it was 40 degrees then it was probably somewhere in the region of 39 -41 degrees! >

My opinion is 'piffle'. We are not talking about the front window, but someone sitting in a cabin looking out of a small oval window at a wing and a (possible dodgy) horizon and estimating a bank angle, in a possibly unfamiliar aeroplane? Purrlease- I wouldn't try it myself!

We may rest assured that <some suggestion that there was a fairly heavy airprox over Dulwich.....> REALLY = "I was having a quiet fag in my garden and I tort I taw a Puddy Cat (sorry, 2 aeroplanes rather close)". Maybe the fag was one of those funny ones, but no incident whatsoever took place, so why are we wasting 3 pages on this garbage?

anengineer 22nd May 2004 04:55

Well, judging from some of the replies here, I'm more concerned about the level of arrogance shown. The original poster asked a simple and polite question. To some it appeared as just a 'knee jerk reaction' to perceiving two aircraft to be too close. What I'm reading is a worse 'knee jerk reaction' from some (presumeably) professional pilots who are probably more likely to be driving me though the sky than the original poster. The impression is one of sheer arrogant dismissal.... NOT what I, as a passenger, consider a positive attribute in a pilot. Thankfully, others here show a far more sensible attitude.

This theme always crops up, a non-pilot posts some snippet, a rumour perhaps and there's always some 'Cpt. Bolshy of Biggin' waiting to dive in and dismiss (and preferably ridicule whilst he's at it) the temerity of some oik to question anything.


...and as for 'wasting pages' and 'bandwidth', erm...

...what exactly is being 'wasted' ?

PPRuNe Pop 22nd May 2004 07:36

Funny how things happen.

I intended to post very similar points that anengineer has made but he saved me the trouble. :)

His points are well made. Professional pilots should not throw arrogance in the face of genuine people. A question might well be misplaced or even stupid, but to the questioner it is not, and for that reason, if no other, it should be treated with respect.

I remember when I was a child and loved the sight and sound of aeroplanes, all I wanted to do was fly. When it became a major part of my life I think I can truthfully say that I have never once brushed aside a question from an eager youngster. And that people, is just as it should be.

NEVER give the young or uninformed the impression that pilots are a bunch of self centred arrogants prats - get my point?

HEATHROW DIRECTOR 22nd May 2004 08:02

I gave a quickie response to indicate to the reporter that such sightings and his concern were fairly commonplace. I was in the OCK hold a few weeks back and there was an A310 1000 ft above and just outside us. Each time we turned our left wing went up and his right wing went down... and it looked every bit as if our wing tips would touch. I was on a smaller a/c (A320) so from the ground it could have looked horrific. Scientific explanations are hardly necessary - someone has had a fright and simply needs re-assurance that all was well.

One of the phone calls I received at Heathrow was from a guy who referred to himself as a "Senior BA Captain" who had been driving across one of the Thames bridges in central London and claimed to have witnessed a "dangerous airmiss between a light a/c and a Heathrow inbound". Light aircraft and helicopters fly back and forth under Heathrow inbounds all day long under ATC control and at that sort of range there was probably 2000+ ft between them. I advised the Captain that there had been no problems and explained that vertical separation existed between such flights. He would not listen to reason and was absolutely adamant that he would be filing a report!! I never heard any more...... wonder if he's reading this now?

Remember what Father Ted said to Dougall - "This is small but that is far away..."


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