Ueberlingen collision Trial started

[ATC Watcher]

The trial is prosecuting for the moment 8 Skyguide ( the Swiss ATC Service provider ) officials. after the collision that occured on 02 July 2002.

It Started last Tuesday, with the audition of 2 senior management staff of Zurich ACC, who rejected all responsibility, and declared that the " fault" lies solely with the air traffic controller on duty that night ( who unfortunately will not be there to defend himsef ).

But the judge seem to want to look deeper into the system, and he could overturn some stones.

The trial is expected to last a few weeks.

[120.4]

"It Started last Tuesday, with the audition of 2 senior management staff of Zurich ACC, who rejected all responsibility, and declared that the " fault" lies solely with the air traffic controller on duty that night ( who unfortunately will not be there to defend himsef )."

As I remember it, this ATCO was left on his own, without STCA, doing two jobs on radar screens separated by 20 yards and some of the telephone system on MTX? And they want to blame him? In my view his principal error was to allow management to put him in that position in the first place.

If they get away with pinning the blame on this ATCO then every ATCO out there is in deep water: It means ATSPs can run their system in a seriously flawed state without being liable when the guy on the front line is unable to make up for those inadequacies. It is not the job of the ATCO to make up for shortcomings in ATC system design and that he should have been asked to do so is unacceptable.

If their defence wins the day then it is time to hang up the headset.

:mad: :mad:

.4

[poorwanderingwun]

Sounds as though we may have some parallels here with the 1976 Zagreb collision..

[BEagle]

Whilst it is true that ATC are primarily responsible for correct vertical separation of en-route IFR traffic, TCAS was introduced as an essential safety complement for those rare occasions when ATC errors occur.

But TCAS is only of any use if the crews know how to use it correctly!!

TCAS RA directions always override ATC instructions!

On 1 Jul 2002, the Bashkirian Airlines Tu 154 and DHL Boeing 757 were on a collision course at FL360. This is what happened in the 50 seconds following the first TCAS Traffic Advisories:

21:34:42 Both aircraft receive TAs
21:34:49 ATC instructs Tu 154 to descend to FL350
21:34:56 Boeing 757 issued “Descend, descend” RA. Crew responds correctly
21:34:56 Tu 154 issued “Climb, climb” RA. Crew continues to descend
21:35:03 ATC instructs Tu 154 to increase descent rate
21:35:10 Boeing 757 issued “Increase descent” RA. Crew responds correctly
21:35:19 Boeing 757 advises ATC they are responding to TCAS RA
21:35:24 Tu 154 issued “Increase climb” RA. Crew continues to descend
21:35:32 Both aircraft collide overhead Überlingen

[Wedge]

I wouldn't read too much into the fact that the Skyguide officials have laid the blame at the door of the ATCO. Given that they are facing criminal charges it's hardly surprising that the central plank of their defence is that the blame lies solely with the late Peter Nielsen. It doesn't of course, in reality, but given this is a criminal trial the defendants don't need to prove anything, least of all that someone other than them was responsible. So don't infer that an acquittal by the criminal court is an imputation of responsibility on the controller.

In reality what happened that night was a combination of systemic failings at Skyguide, serious mistakes by Nielsen which arguably amounted to gross negligence, national differences in SOPs which led the Bashkirian crew to ignore the TCAS RA, and just plain bad luck.

[120.4]

Wedge

It seems that you have a greater grasp of the detail of this than I do. You have made a strong statement about Peter Neilsen's part in the accident - I wonder if you would share the detail of his mistakes? Could it in any way be argued that his mistakes were provoked by the situation he was in?

What I find incredible is that (as I understand it) he was required to be monitoring 2 radar screens, 20 yards apart by himself. Surely, that is an unacceptable situation for any ATCO to be put in and it ought not to get through the safety case?

As far as the management is concerned, it seems to me that they willingly removed a number of the safety nets in order to get essential work done without first providing mitigation of the increased risks. That action directly exposed the system and Mr Neilsen. Regardless of what other errors were made, that strikes me as negligent.

.4

[ATC Watcher]

Oh dear ! The subject of this post is the trial, not to re-do the investigation.
I suggest that you look again in the Bfu report to find your answers.

TCAS flaws have been highlighted as a result of this collision and it is very simplist to suggest, as it is done here, that the757 crew responded correctly and the Tu154 did not.

As to the supposed "gross negligence" of the controller on duty, let me just say that this view is not shared by the vast majority of the people involved in the investigation, and even ,as far as I can see, also not by the defence lawyers.
How the judge will go is still uncertain.

[NigelOnDraft]

TCAS RA directions always override ATC instructions!BEagle... Rightly or wrongly, I interpret your post as putting the blame on the Russian Flt Crew :eek:
Can you confirm you are basing that allegation on definite knowledge that at the time, the Russian Company SOPs, authority legislation, equipment and Training were of a similar status to that on which you base your statement?
Without having investigated the accident in great depth, but to some degree, then it seems there were ATC "system" failings that enabled that system to fail. That TCAS then failed as well was unfortunate, but it was a relatively "immature" system, particularly for say some former "Eastern Block" nations/operators, and "rules" to which you and I operate, especially today, might not have applied then, to that crew... :sad:

[Human Factor]

At the time, my company SOPs were that a TCAS RA was to be followed unless the target could be identified and was no threat. That SOP has since changed removing the proviso. Other companies have done the same.

[W.R.A.I.T.H]

Re the Russian SOP w.r.t. TCAS: I recall from some discussion groups a few years back that there had been a dispute on the flightdeck of the Tu-154 between the captain, PF and the check captain, acting as the PNF. The check captain allegedly overrode captain's decision to heed the TCAS and insisted to descend as instructed by ATCO, exactly in line with the Tu-154 manual. Also as far as I remember, the main SSR was u/s and a backup unit was being used (not sure if that meant the processor-screen or a complete radar-feed).

Found the report, here (http://www.bfu-web.de/cln_001/nn_41544/DE/Publikationen/Untersuchungsberichte/2002/Bericht__02__AX001-1-2,templateId=raw,property=publicationFile.pdf/Bericht_02_AX001-1-2.pdf), in German, it states three systemic causes: the TCAS issue compounded by failure to standartize (in the end, who will pressure Russia) requirements and harmonize units, and the other two are down to the Skyguide management. I hope the name of P. Nielsen comes clear out of this trial too.

[kingair9]

exactly in line with the Tu-154 manual


Being a PPL amateur I had the chance 4 years ago to buy a sim hour in the TU5M sim of S7 for peanuts just out of curiousity. The sim then had TCAS but it was not included in any checklist whether it works or not so I asked the pro riding with me about it. His statement was more or less "oh, yes, we have it but if it is u/s we go anyway". This, well noted, on a "better" airline going to the "West" frequently.

Question ímho is therefore - did Bashkirian drivers ever go a REAL trainig in it, ie did they really learn to obey it???

(NOT blaiming them but possibly their company!!!)

[NigelOnDraft]

His statement was more or less "oh, yes, we have it but if it is u/s we go anyway". This, well noted, on a "better" airline going to the "West" frequently. In my company (a well known UK one!) it is permissible to fly with TCAS u/s for a period of time, and I have done so a few times. NB we all used the fly without TCAS pretty safely a few years back, and we still have Mode C v the other aircraft's TCAS.
If you can get 2 TCAS u/s aircraft in the same part of the sky AND an ATC "system" failure sufficient to cause a collision, it's not your day :(
As HF says, even in the West, training and SOPs have been tightened post this incident. In the East, life tends to be more "control based" and a larger cultural change needed to blindly obey a piece of kit contrary to an ATCO. Hanging the Russian crew out to dry (also dead) is as bad, IMHO, as hanging the ATCO out...

[Tarq57]

If you can get 2 TCAS u/s aircraft in the same part of the sky AND an ATC "system" failure sufficient to cause a collision, it's not your day

And yet, something all too similar happened again.(Brazil)
I pray the aftermath of the Uberlingen collision doesn't happen again.(with respect to Mr Nielsen's fate.)
At least in part due to the media, IMHO.

[BEagle]

Although there was an ATC failure, Mr. Nielsen tried his damndest to cope as best he could.

The Bashkirian Airlines crew had all received TCAS training and the TCAS operating manual used for their course was quite specific concerning RAs and contradictory ATC clearances - even though the Tu-154 manual was rather less so. There was a 'seat swap' in progress as the co-pilot got back into his seat after the first TA - he made the point several times that the subsequent RA was very specifically ordering a climb......

Read the report in full, I would suggest.

[BSD]

This question has been troubling me since the accident, hopefully someone more knowledgeable of ATC than myself can resolve it for me.

Was it not the case that the Tupolev had been allowed by the previous sector to cruise at a non-standard level?

That being so, on transfer to the sector in which the accident took place, should that not have been made clear to the receiving sector?

Naively, I would'nt have that you'd be handed over to another sector at a non-standard level without either their acceptance, or an instrution to adjust ( climb/descend ) to a standard level for the sector you are entering.

There are many areas of the world where non-standard level cruise is widely-used, and indeed encouraged. I've used it myself on several occassions, but always in the perhaps misguided notion that in addition to TCAS, we enjoyed this further protection.

Any thoughts?

[Clandestino]

According to MEL of the aircraft I've flown, it is allowed to dispatch with TCAS inop, but ATC permission has to be sought and in Europe it is usualy given.

larger cultural change needed to blindly obey a piece of kit contrary to an ATCO

That piece of kit is intended to save lives when conventional methods of aircraft separation have failed and that's what everyone needs to know, regardless of his cultural background. I find it hard to believe that russian peacetime culture puts obedience to authority above self-preservation. More likely the russian crew was never fully acquainted with the TCAS principles of operation and procedures to be followed in case of RA. Not their fault, mind you - it was fault of their trainning dept and Russian CAA.

At the time, my company SOPs were that a TCAS RA was to be followed unless the target could be identified and was no threat. That SOP has since changed removing the proviso. Other companies have done the same.

Mine didn't. Since we got TCAS in 2000. it was always policy to follow TCAS RA unless it sends you toward terrain, thanks to safety pilot who understood TCAS very well.

That TCAS then failed as well was unfortunate, but it was a relatively "immature" system

TCAS flaws have been highlighted as a result of this collision

It was not immature and it didn't fail over Ueberlingen - it worked as designed. My apologies for perhaps being narrow-minded, but I can't see flaws in TCAS itself in this case.

Sounds as though we may have some parallels here with the 1976 Zagreb collision..

Indeed, at ZAG ACC there were only 2 ATCOs covering consoles usualy occupied by 6 of them and just as Adria DC-9 was handed over from mid to upper sector an told to stop sqawking alt (per procedure at the time) one of them had to take physiological break. It didn't help much that the overworked remaining ATCO panicked and issued instructions to DC9 crew that lead to collission. He was later sentenced by Yugoslav court to 5 years in prison but was released after year and half, after retrial. Other controllers and ATC organzation were acquitted at the first trial.

And yet, something all too similar happened again.(Brazil)


Not quite similar. To have coordinated TCAS resolution advisory manuevre, there have to be two aircraft equipped with TCAS and S mode transponders. RA's can be issued against altitude reporting targets and with plain A mode there can only be traffic advisory. And if transponder is off (as it seems to be case in Brazil), TCAS is helpless.

[AN2 Driver]

Been in the TU Sim several times (other sim however) and talked to a lot of TU crews. All of them concurred that if a TCAS goes off they are not going to heed ATC commands but to follow TCAS no matter what. One put it brutally by saying "Why should I listen to the one who put me into a situation for the TCAS to go off in the first place?" While I find this a tad one sided, as a TCAS alert can be triggered by pilots mistakes as much as ATC mistakes, the gist of it is, when a TCAS goes off I'll follow it first and ask questions later.

Obviously the worst case scenario is if one guy follows TCAS and the other doesn't. So, if you get a TCAS RA and can't rely on the other guy to act on it, then things will go pearshaped very quickly.

I reckon that the Ueberlingen accident has brought that message home to just about all the TCAS users who care to read up on it. So let's hope that this will never ever happen again.

[Tim Dawson]

In fact, if one guy follows the TCAS and the other doesn't, you'd probably still be alright most of the time. It's when one follows it and the other _does_ take action, but the opposite action than they should, that things will go pear shaped.

[ATC Watcher]

On the TCAs issue : caution not to mix pre-Ueberlingen ( July 2002) ACAS training guidelines , with post Ueberlingen. The current ones are quite different.

At the time, the training guidelines were not that obvious : an RA was an " advisory" not a " command" to be followed with closed eyes regardless of anything else. The contradiction between an ATC clearance" against RA direction was not that clear.

Most AIPs ( including the German one that legally was in force at the time and place of the collision ) said that unless in Emergency pilots should not deviate from ATC clearances, and an RA was never defined as an emergency.
In our case the ATC instruction was BEFORE the RA. So a bit of kindness for our Russian colleagues.They did some things wrong perhaps, but so did everybody else that night. But all this is in the BFU report.

Back to the original thread :

Latest from the trial : 7 of the 8 defendants accused the late controller on duty as the only person responsible. . He turns out to be the perfect scapegoat .Even his colleague ( the one that went to bed at 2300 ) said it was all the other controller fault, as it was up to him to check what the technicians were doing and what were the consequences. The judge asked him " But why did not you ask them yourself ,as when you went off duty you saw all of them waiting to come in the OPS Room ? : his reply :" It was not my task, and even if I had asked them, I would not have been able to understand their responses , I am not a specialist "

Pathetic defense ...I do not know which lawyers are advising them, but I do not think this will impress the judges much.

[kontrolor]

as always...there was complete set of mistakes, but ultimately controller on duty cleared two planes on conflicting route to the same level. this tragedy is sad reminder for all of us professionals. and a lesson - they will always blame the last in the chain.

[keepin it in trim]

Only a couple of months ago, in spanish airspace, I heard another aircraft advise atc "tcas climb" and the controller came back and told him not to climb as he would go clear of the other traffic. If I hadn't heard it myself I wouldn't have believed it!:confused:

[ATC Watcher]

Kontrolor :
ultimately controller on duty cleared two planes on conflicting route to the same level. .

Not quite correct my friend, he did not clear them together . The 757 was cleared off route direct by Geneva, and the Tu154 cleared off route direct by Munich , on the strip he had them 7 minutes appart .When he discovered ( very late ) that they were in fact coming together , he cleared one down , not both... ( all this ,and more , on the BFU report ).

I do not agree with blaming the last one on the chain, wether it is a controller or a simple hand deck sailor ( Like the one that closed the door , also too late, of the "Herald of Free Entreprise ") because it does not solve anything, and confort the real responsibles in their views that since they have not been made responsible, there is nothing to change to prevent it from happening again.

Now the latest on the trial :
Tuesday the prosecutor made a strong requisition against the od Skyguide management, talking about " a negligent climate in the entreprise " he requested 15 months jail suspended sentence for the 3 top managers, 12 months for the maintenance head that authorised the systems to be switched off ,8 months for the other controller that went on break and 6 months for the 2 others accused .

It is still too early to say which way the Judge(s) will go.

[Frangible]

I don't believe the official report made anything of both planes being on the same flight level. Why, like the GOL 73 and the Legacy, were they on the same FL in the first place and not at odd or even FLs according to which side of the north-south line they were heading?

[Carnage Matey!]

Because they were both heading west?

[Green Guard]

ATC Watcher
"the757 crew responded correctly (to TCAS) and the Tu154 did not"

Yes?

But you fail to say that:

757 crew responded incorrectly to ATC, while the TU154 responded correctly to ATC,
they were on the same frequency, weren't they?

This accident actually proves that almighty TCAS is not fail-safe at all.
You need one or both or more aircraft to obey TCAS command,
to get out of a collision
but if one of them starts dangerous direction descent or climb,
here you have it...

[ironbutt57]

How did the 757 crew respond incorrectly to atc??

[BEagle]

Green Guard, please tell me that you don't fly or control commercial air transport aircraft.......:eek:

[Nubboy]

Green Guard, please tell me WHAT the 75 crew did wrongly, with regard to ATC?
I regard TCAS as I do EGWPS. It's an automated system thats looking out for me. When it tells em to do something, it normally means failure to follow its instructions means you die. Period.
People miss things and get them wrong.
The ATC'er saw a conflict and kept trying to resolve it, long after he should have shut up.
The TU crew had a conflict, TCAS and ATC, and never resolved it.
THE 75 crew did everything they should have done and died.
ICAO must ensure that such an avoidable trgedy doesn't occur again. If you can't, or won't comply with TCAS RAs, THEN YOU SHOULDN'T BE IN CONTROLLED AIRSPACE.
Regardless of the faults with the ATC system that night, TCAS was the LAST safeguard. By choosing not to comply with the HARD RA, for whatever reason, then that safeguard was wilfully removed.
Apart the question of different languages on frequency TCAS is not only a lifesaver, it's also our best on board tool for Situational awareness. Some of our A320's have (had?) a software variant which wouldn't display TCAS targets if the range on the ND was over 40nm. On those aircfraft I never left the range over 40nm once I'd verified the next TO waypoint. Surely basic airmanship dictates that you look where you're going, using all the tools available to you.
I too, am very unhappy about any MEL alleviation that lets you operate without a fully serviceable TCAS system.

[MartinBaker]

Hi all
just a short note regarding this painful case.
When investigating the LX498 crash (Zurich, 10Jan 2000) we travelled to Moscow, St Petersburg and Cisinau (Moldova) as the Captain was a Moldovan national and former (pre 1989) Aeroflot regional pilot.
Our knowledge of selection, training and operations in the FSU needed to be updated and documented.
This was an enriching and valuble experience which highlighted the professionalism of personnel, operations and proceedures in FSU and the use of Russian equipment.
However it also highlighted the different approach to HUFAC and its application. In particular a, then slightly 'old school', prevalent sceptiscism and mistrust of electronic in avionics. There was a very human oriented approach to most problems encountered in flight ops.
In particular TCAS was viewed as a gadget foisted upon Airlines and operators that (from Eastern European and beyond ops) seemed to be un-necessary. It was viewed with almost disgust and its challenge to human reasonning questionned!
We imagined the Uberlingen scenario where a pilot would listen to the human controller and not the TCAS command with its tragic consequences, and felt that this was a note-worthy point to raise with authorities in the west however it is/was one of those warnings lost in 'paper-space' and unheeded until proven correct....unfortunately in our own 'back garden' and not somewhere on the other side of the world!
This was 7 years ago and this attitude has probably died out now, and unfortunately with the 'watershed' accident in Uberlingen the point is made clearly regarding TCAS and its implications.
IMHO any one who still questions TCAS should rethink his/her position......on the ground, before joining the rest of us in an ever more crowded sky where we each survive thanks to each others (ATC included) professional dedication.
best regards
MB

[Lon More]

Many pilots from the old East block countries were bought up in a much more rigid system of absolute obedience to instructions from the ground. If in doubt follow your training. At that time TCAS was still seen by many as riddled with faults ( Dallas Bump etc.) and as a non-revenue producing system not much time would be spent on instructing in it's use.

From an ATC point of view there was also initial resentment as it was seen by many as something that reduced our authority. Again, how much time was invested in training the actual controllers on the workings of the system From memory, most of the info we received came from ICAO posters and a campaign by EGATS (Merci, ATC Watcher) than from management. How much actual training did Peter Nielsen receive?

looks like the initial statements by management at the trial were a poor attempt at CYAS by muddying the waters

[anotherthing]

Pure speculation regarding this tragic case, but I was reliably informed a few years ago that to fly in certain parts of European airspace, A/C above a certain weight/seat allocation had to have TCAS fitted.

It was believed that some airlines fitted the kit to permit them to fly in said airspace, but did not train the crew in the correct use as that would have added more expense.

I am not in any way saying that this is what happened here - but in a regime whereby authority is everything and a way of life, it must be difficult, especially with regards to newish technology, to ignore commands/instructions given (in good faith) by an ATCO etc.

Fortunately, as Lon alludes to, Crews and ATCOs are now more aware of what should happen during a TCAS event.

Although a horrific incident, is a court case and possible prison sentence the best way to end this? Open reporting of incidents is what is needed - the threat of disciplinary action, either by company or courts, is not conducive to this.

Also, so many years have passed, and the ATCO involved is no longer with us - this leaves an instant and convenient scapegoat, which may mean that the truth, and indeed lessons to be learned, may never surface.

[ATC Watcher]

ACAS Training issues, Oh yes... that was and still is a problem.
A study made by SOFREAVIA in 2005 based on on board recordings from 4 European airlines ( 2 majors and 2 commuters ) over 4 years ( 2001-2004) showed that only 28% of the RAs were correctly followed by the pilots and in 10% of the cases the pilots choose not to follow the RAs or acted opposite to it. Althought the percentages might be better today, seen the incidents reports we read, there is still a lot of room for improvement, and not only in Russia...

Frangible :
I forgot to mention that to read the BfU report you must have a bit of aviation knowledge. It was not made for journalists or the common layman.
Green Guard : you said : 757 crew responded incorrectly to ATC
Please expand : I do not know what you are trying to say.
Back to te trial :
Yesterday was Defense day :
Not surprisingly the defense lawyers put all the blame on the controller on duty, to prove that the management they defend was not responsible.
One said " The controller created himself the problem . he committed many large errors and contrary to what the prosecution said , he was not overworked or stressed "
Another quote " he made himself responsible for the severe faults he made which ultimately led to the catastrophe "
Another lawyer said : The telephone was not a factor , he should have put the Airbus A320 on hold while solving the telephone problem "
I always like when lawyers are telling us how we should have done our job, Afterwards of course.....

[Green Guard]

Quote:
"757 crew responded incorrectly to ATC "

because ATC never asked that crew to descend. It was TCAS that made them to descend.

It is easy to give statements from in front of our computers. But on every day of our duty we always follow ATC instructions (whether we are from West or East), and any TCAS TA makes us see the picture, before RA comes out. We can all swear to act exactly like the 757 crew did. But in the heat of moment or a pressure, TA, RA and in the same time LOUD command from ATC, to start and expedite descend they did what they did.

And 757 crew did everything correct regarding TCAS and died.

We all need even love TCAS. "I can see you on my TCAS"

Main question here is how this tragedy could have been avoided. We all know one answer:
If both parties responded correctly to TCAS and incorrectly to ATC.
Second answer may be about new TCAS perhaps.

[av8boy]

"757 crew responded incorrectly to ATC "...because ATC never asked that crew to descend. It was TCAS that made them to descend.

Main question here is how this tragedy could have been avoided. We all know one answer: If both parties responded correctly to TCAS and incorrectly to ATC.


Oh nonsense.

To follow a TCAS RA in the absence of any ATC instruction at all is nothing like an incorrect response to an ATC instruction. Hell, to follow a TCAS RA which is exactly the opposite of an ATC instruction is exactly the right thing to do! We've all agreed (us controllers and you pilots) that a TCAS RA supersedes an ATC instruction. Therefore, the 75 crew did what we all depended upon them to do, and the TU crew did not. Think of it this way, a TCAS RA is the ultimate ATC instruction. It trumps all others. For crying out loud, it erases the ATC instruction. How can you respond incorrectly to an ATC instruction that has been erased? We ATCers support that idea. To echo BEagle, PLEASE tell me that you don't fly or control transport aircraft...

Where the hell is Jerricho when you need him?:ugh:

And Nubboy...

The ATC'er saw a conflict and kept trying to resolve it, long after he should have shut up.


Actually, until we all have some technology in place that tells us you guys are getting an RA, we're not going to be shutting up. That's because we have no way of knowing whether or not you're getting the RA up there or not, and we're accustomed to trying to resolve the situation as long as there is an opportunity to do so. So I beg you, ignore me. Tune me out. Follow the RA. But know I'll keep chattering...

-Dave

[Avman]

Green Guard, I'm all for intelligent debate, but you're coming out with complete and utter garbage proving that you know pi$$ all about which you are talking about. You make my blood boil :mad:

[Nubboy]

Cheers
Dave
I fully take your point about not knowing if wehave an RA or not.
Isn't the technology there to broadcast/receive teh TCAS instructions so that at least you could be shouting in harmony with machines instead of against, as was so painfully the case here? Just a thoughtfor the techies.
As for Greenguard..........thank God I'm part time which reduces, statistically, the chance of ever having you on any side of a frequency I might be using.

[FlyGooseFly!]

I reckon most posters are forgetting the whole point of this thread - it's about a court case and not about the facts as they see them.

Yes, the SOP's will be gone over and may be criticised along with the actions of the pilots but I believe the overiding factor here is once you have agreement on the regulation of the skies in that we have ATC - it's their ultimate responsiblity to prevent collisions - no matter why or how - the guy in charge at the time will be blamed.

On top of that we have the additional National interests and affronts of "we wouldn't do that kind of thing here" and "how dare you insult us," plus and increasing lobby of folk who seem bent on indicting company directors at every turn to further some kind of vendetta against corporate business.

[kontrolor]

757 crew never stated that they are in TCAS descend.

and as far as same level - both aircraft were cleared to FL360. so he should have put more attention to them.

but generaly - I'm working in relatively small ACC unit, but nobody would allow such degradation of service without backup. I think Zurich controllers accepted what the managment threw at them and result was a tragedy.

and I'm not blaming the atco, I just wanted to emphesase, that he had a responsibility and he failed to use all the resorces he had in order to prevent the collision (ultimately).

[BEagle]

kontroler, that is not true.

The accident report clearly states that the B757 crew did indeed make such a call:

21:35:19, Crew report TCAS descent to ACC Zurich

[Nogbad the Bad]

I think Zurich controllers accepted what the managment threw at them and result was a tragedy.


Chances are they had no say in the matter !!

:mad:

[kontrolor]

21:35:19, Crew report TCAS descent to ACC Zurich

when it was already too late. They were suppose to announce it right after they 've commenced descend. but - anyhow...too many things went wrong that night...

Chances are they had no say in the matter !!

there is always a mean to do it

[BEagle]

Again, kontroler, you are wrong. Have you read the full accident report? If so, you will see that the crew made their call as soon as practicable, due to the level of RT traffic on the frequency in use.

The 757 crew reacted correctly, the Tu-154M crew did not.

[kontrolor]

I checked again, you are right. they called in time. but this doesn't resolve the basic problem (the most obvious) - P. cleared both on same level and then didn't observe what was going on. Clearing DHL to fl340 would be the easiest solution. but we can debate about the reasons why P. didin't do this, the fact is that passengers are dead and so is he. Don't get me wrong - I'm not blaming P. for being the the only responsible for the crash, but it is not fair from ATC community (to which I belong) to point to all other factors except this.

[120.4]

Nogbad

Isuspect you are right to suggest that this was presented as a fait accompli.

Of course, this is really what unions are for; not just to negotiate good Ts & Cs but also to ensure management don't expose individuals by operating the system without necessary safeguards. Mr Neilsen didn't make the decision to do that but I do believe he should have refused to accept it.

Hypothetical scenario:
ATCO comes on duty, deselects the phones, switches of the STCA and then tells another sector 20 yards away that he will do his sector at the same time. A mid-air collision results. The ATCO's defence? He hasn't any. The responsibility lies with those who take the decisions to operate the system wthout appropriate safeguards. In this case it was not Mr Neilsen.

Kontrolor
My understanding is there was 7 minutes betwen the estimates of these two aircraft? If that is correct then accepting them at the same level is not unreasonable in a radar environment. Having said that, human beings will make mistakes and this is precisely why systems must never be run without reasonable slack and leeway.

I'd love to see the safety case that covered the circumstances that existed.

I have no vendetta but I am anxious to ensure that neither myself or my colleagues end up in jail because of irresponsible management decisions. They must be seen to carry the responsibility for this or a dangerous precedent is set.

.4

[kontrolor]

7 minutes is (by my standard) not enough to be easily taken into the state of such relaxation, to physicaly move to another console and do completely different kind of controlling. I don't leave my console even on night shifts when there is no traffic in more than 20 minutes.

[Avman]

Kontrolor, it is obvious that you are making statements without being fully aware of what happened that night. Before making any more irritatingly silly comments why don't you try and acquaint yourself with ALL the FACTS that led to this terrible tragedy!

[6000PIC]

The management of Skyguide , in my opinion are guity of negligence plain and simple. If they want to pass the blame on to the deceased controller , it speaks volumes regarding a lack of professionalism and accountability in the MANAGEMENT of the hardware , liveware and software at their facility - no wonder this accident happened with a corporate attitude such as this...
Still with this accident , it suprises me that the issue of the logo lights on the 757 as being MEL`d wasn`t mentioned. As you can see from the report , the 154 basically took the ( dark ) tail off the 757 , which when recreated for television , erroneously showed a brightly lit tail. Perhaps a brightly lit tail at night might be a good idea , in the meantime contrary to my company sop`s , I keep my logo lights on above FL 100 , see and bee seen as a last resort ??
I hope nobody goes to jail , these`s been enough pain and suffering already , an acknowledgement of guilt and accountability would suffice for me , and a big financial settlement for all the families of the deceased would be just.

[Dream Land]

Although it's unfortunate that ICAO hadn't taken more of a leadership role in TCAS operation, history has now provided ample proof that all pilots need to be on the same page for TCAS to be an effective tool. I feel Mr. Nielson was also a victim in this terrible tragedy, any ACC facility that allows a controller to man two positions as outlined should be held responsible.

If they didn't have the money to properly staff the facility, I hope that the judge sends them a strong message as to how much it costs to improperly staff the facility.

[kontrolor]

Kontrolor, it is obvious that you are making statements without being fully aware of what happened that night. Before making any more irritatingly silly comments why don't you try and acquaint yourself with ALL the FACTS that led to this terrible tragedy!

I'm fully aware of ALL the events that night, even those which were not publicized. All I said, and this may not be fair to P.N. who paid the ultimate price (as the passangers did) in long chain of events. but he was PART of that chain. And all I said was that 7 minutes difference in estimates on crossing tracks, even in the night shift IS JUST NOT ENOUGH to feel comfortable and even to leave sector. And I also said, that in my country this wouldn't have happened, because the working culture. We wouldn't have accepted such arrangements as Skyguide has imposed upon his workers. In Switzerland one keeps his/her mouth shut and does nothing I suppose. Our sector is far less buisy as Zurich one, but we are NEVER less than 4 on night duty. NEVER! Regardles of how I feel about P.N. as colegue, he cleared both planes to FL360 on crossing tracks and then left the sector! It is obviously that the culture "I have to do all that it is expected of me" has a lot to do with this tragedy. And please, never again accuse me of not being aware of what was going on there. You might visit one of IFATCA onferences and got briefed by Zurich controllers in person.

[Dream Land]

cleared both planes to FL360 on crossing tracks and then left the sector I watched a Discovery channel show about the incident, never know how accurate the depitction is but they showed him initially taking the position working only the two aircraft (the two invloved in the accident) and it struck me as a rather odd thing, to clear DHL to FL360, the same level as the only other traffic in the sky. :confused:

[Avman]

I'm fully aware of ALL the events that night, even those which were not publicized.

So am I.

We wouldn't have accepted such arrangements as Skyguide has imposed upon his workers.

Well you're very lucky. In many organisations, because of management culture, you really don't have a choice (other than quit). I've seen what happens to colleagues who openly (and quite rightly) confront management on safety issues. If the remedy might impact on reputation (delay statistics), cost effectiveness and such like, they are either conveniently ignored or, if insistant, branded trouble makers and dealt with accordingly. Consequently, the remainder (especially those with mouths to feed) stay quiet and just hope that they survive another shift!

[120.4]

To ensure we are all well informed, may I suggest the following link as good reading for all interested, especailly if you currently hold the view that Mr Neilsen was to blame for this accident. It is a review of the BFU report, carried out by Professor Chris Johnson.

http://www.dcs.gla.ac.uk/~johnson/Eurocontrol/Ueberlingen/Ueberlingen_Final_Report.PDF

3 quotes:

"The accident was caused by a combination of the under-manning and a failure to recognise the risks associated with the profound system changes and lack of normal system support as a consequence of the SYCO flight plan processing system upgrade."


"The conditions that make this event more likely include the fact that the paper control strips for the B757 and TU154M do not show any apparent conflict."


"We concur with the BFU that the Swiss authorities had well-documented procedures and principles that would encourage the development of a sound Safety Management System. These principles were in accordance with ICAO and EUROCONTROL guidelines. However, the Swiss ATM organisations lacked the experience and the personnel to implement those procedures. Partly as a result of this opportunities were missed to learn from two AIRPROX incidents that had similarities to the events before the Überlingen accident.


6000PIC - I'm with you; I hope nobody goes to jail. What I believe is essential is that the truth is known and responsibility acknowledged.

.4

[ATC Watcher]

This thread is about the trial, it was not meant to re-open the investigation using rumours and self invented rules.
There is very little unknown , very little questions remaining unanswered in that accident , and the investigation team did quite a good job. Zurich ACC learned their lessons, and we all know the shortcomings .
No need to do everything again .

Kontrolor, :
If you are not happy with 7 minutes in Liubjana ,fine, in other Centres some are happy whith 5 min. You do the nightshift with 4 per sector (:hmm:) and can refuse easily management pressure. Bravo. But please do not judge others whithout knowing their working enviroment. And I can assure you that on the morning of the 2nd July 2002, there were many , many ATC centres in Europe , including large ones, which said " This could have exactly happened to us ". I am glad to learn this was not the case in Liubjana.

BEagle : The 757 crew reacted correctly, the Tu-154M crew did not.
I see what you are trying to say but unfortunately this is not that simple.
The 757 crew was not completely white and the Tu154 not completely black .
It is not that clearly said in the report, but this was the subject of a special briefing afterwards leading to the subsequent changes in ACAS training guidelines.

As I said earlier, everybody did mistakes that night. Some small, some big, but no-one was really totally immune. The early days of blaming the Tu154 crew for everything proved to be not that evident . One has to see this in the context of the ACAS training guidelines in foce then , not the ones we have today ,and largely modified as a result of this accident.

Now back to the subject :

Today Wenesday 30 was the last day of the public hearings in Buelach. The lawyers of the last 2 accused repeated the same story : the controller on duty is the " only one responsible for the collision , therefore my clients should not even be here "
The only interesting comment : Zurich management had argued that they did not warned specifically the 2 controllers on duty that night of the work planned,and its consequences, but that they had to look at a publication board where it was explained . The controllers apparently failed to look at the board. Well, it turned out that it would have made no difference , as the notice did not say when the work would take place and which systems will be affected.
Another Zurich management poor show.

This is the end of the public days.

The judges did not say when to expect the verdict.

[ettore]

6000PIC - I'm with you; I hope nobody goes to jail. What I believe is essential is that the truth is known and responsibility acknowledged.
No one will go behind bars, since the attorney asked for suspended sentences only. I wonder if a bunch of reckless people sending a school bus into a ditch with fatal consequences would get such a mild treatment.:ugh:

[Dream Land]

Quote from the Brazil mid air collision: by Defense Attorney, He added: "The fact is that air traffic control placed and approved these two aircraft on a collision course, on the same airway, and altitude traveling toward each other. That is the overwhelming, obvious root cause of this accident."

[Tarq57]

Quote from the Brazil mid air collision: by Fedral Judge, Murilo Mendes
Quote:
He added: "The fact is that air traffic control placed and approved these two aircraft on a collision course, on the same airway, and altitude traveling toward each other. That is the overwhelming, obvious root cause of this accident."
I think you may have reported the wrong source. According to this thread: http://www.pprune.org/forums/showthread.php?t=278417
those comments are attributed to the defense lawyer.
(Although I certainly hope the judge is inclined to agree!)

[ironbutt57]

Unless the logo lights on the 757 were mdd'd they would have been on.

[Yaw String]

Been there, seen it,done it and luckily in my case, survived!
It caused me to open a thread back then "RA,to follow or not to follow"
In my case was a B767 operated under Italian FTL's therefore you can assume i was very tired!
SantaMaria cleared a Spanish A340 to climb into conflict from 1000 ft below, on converging course. I was awoken from my short power nap by my F/O who decided to include me in the scenario as other aircraft was 500 ft below and climbing. Resulting RA put me in a descent followed by the same action from the A340 as he realised the mistake and also descended, probably just as he got the climb command! I suspect that his action was also driven by his knowledge that he was about to infringe my airspace!
The resulting aerobatics will remain with me for life but, in this case we all survived!

[Dream Land]

Markjoy, oops, sorry, you are right. :\

[ironbutt57]

As one of my colleagues so blantlantly put it...'if it werent for TCAS the accident woudnt happened...:ugh::mad:

[Ignition Override]

Would an avionics question be pertinent here?
At our US company, the TCAS was out of service on the last leg, per MEL, on my last trip (a 100-seat turbofan). Only the normal, good old transponder mode C etc worked.

The MEL book had only one restriction, no PRM (parallel approaches, reduced lateral separation, radar monitored) approaches are allowed. No other limitations are required by the FAA. There was no mention of RVSM, altitude limitations (i.e. FL 290), autopilots etc.

It surprised both the First Officer and me that there were no other conditions, in order to operate 1,000' from aircraft at all altitudes. The RVSM is fairly new for us, and requires the digital altimeters and the large clean areas around static ports etc, but TCAS has been around many more years.

Does it seem like there is a contradiction here somewhere? Why would TCAS not be required to be operative, when we had no restrictions except for prohibiting PRM approaches? :hmm:

This just now came back to me. One of our pilots who worked as a "Cruise FO" for two years with a 'north European' airline around '90-'91 was on our jumpseat about 14 years ago, going to ABQ. One dark night over eastern Russia the Captain went back to either sleep or puff on his pipe. This Cruise Pilot in the left seat was staring out ahead as they climbed to another altitude (before TCAS). "Kr****e" (his nickname over there) told me that he saw the lights of a large jet straight ahead on a collision course. He pushed the nose down a bit and missed the plane by not very much room! He told us something strange about ATC's response, when asked about the dangerous situation. Luckily they were in good VMC.

[green granite]

As one of my colleagues so blantlantly put it...'if it werent for TCAS the accident woudnt happened

There is , in the maritime world, a scenario called "A radar assisted collision", used to happen quite frequently when radar was used for collision avoidance.:ugh:

[NigelOnDraft]

It surprised both the First Officer and me that there were no other conditions, in order to operate 1,000' from aircraft at all altitudes. The RVSM is fairly new for us, and requires the digital altimeters and the large clean areas around static ports etc, but TCAS has been around many more years.
Does it seem like there is a contradiction here somewhere? Why would TCAS not be required to be operative, when we had no restrictions except for prohibiting PRM approaches?I think you're muddling TCAS and RVSM as "associated technologies/procedures". Operating 1000' apart and 2000' apart are equally safe TCAS wise... The TCAS is there to save you when you are operating 0' apart :eek:
TCAS "caused" RVSM problems initially, since 2 aircraft 1000' apart, but slightly wobbling, would give off TAs - quite startling mid-Atlantic with an overtaker from behind :confused: Now corrected in a software change...

[Spitoon]

Back on the thread - any indication of when the outcome can be expected yet?

[what_goes_up]

Hearings are done. Results to be expected by 2nd SEP, I think.

[Al Fakhem]

Interesting item in today's Tages Anzeiger.

http://www.tagesanzeiger.ch/dyn/news/zuerich/786287.html


To pre-empt complaints about "I can't read German", here a brief translation:





Skyguide apparently incapable of learning


Prior to the mid-air collision over Überlingen, Skyguide’s management had ignored all prior warnings by controllers. Are they now doing enough for safety? Doubts are justified.

Nobody can ever say that the mid-air collision at Überlingen on 1st July 2002 came out of the blue:

On 4th January 2002, air traffic controllers at Geneva write a letter to Skyguide management criticizing the practice at Zurich to allow partial control of air space by only one instead of two controllers. “The consequences are far too serious to be ignored”. On 6th March 2002, Skyguide boss Alain Rossier is the recipient of mail from the Zurich controllers’ association. “We are writing in the face of the desolate situation at Zurich ATC (…). Given the current personnel situation, we are unable to fulfil our mission (…). “ The letter goes on to describe a “Wild West” mentality, with everyone doing their job their own way. On 10th March 2002 a number of controllers warn the head of Zurich ATC, stating, “The daily situation is one of chaos”. Working conditions are said to be “unbearable”. And: “it is hard to imagine that we shall get through summer without trouble”.

Within four months, 71 passengers have to pay for the safety issues at Skyguide with their lives. At the time of the mid-air collision, only one controller is on duty – his colleague is on a break. After the crash, the Swiss civil aviation authority (Bazl) stops this practice and outlaws single man operations.

Prior to the Überlingen crash and even thereafter, a fatal pattern emerges: management implements changes without consultation of its operations staff – often in order to save costs. Some controllers voice concerns about safety implications. Management ignores them out of hand. Complaints are met with pressure tactics; people are discredited or even fired. Bazl only intervenes once matters become public – i.e. when it’s too late. This kind of safety culture may be fine for a shoe factory, but in ATC, even the slightest concerns have to be considered and risks eliminated. This is not happening at Skyguide, as demonstrated by the following four examples:



Example 1: Near Miss due to SMOP

On 13th December 2001, not one but two near misses occur within 90 seconds of each other in Zurich air space, a consequence of controller task saturation. The controller involved has been assigned his sector on the basis of SMOP (single man operation), as there is a shortage of controllers on that day. Despite internal criticism, Skyguide management adheres to this system – until Bazl outlaws it after the Überlingen mid-air collision. Skyguide even today justifies its practice, saying SMOP is a “generally accepted ATC practice” and in use in 14 countries, pointing out that Switzerland is one of only a few countries (if not the only one) where SMOP is prohibited in principle.



Example 2: Chaos with Eastern approaches

On 23rd October 2006, Zurich introduces ILS for Rwy 28. This allows Kloten Airport to be approached not only from the North and South, but also from the East under poor visibility. On 10th October 2006, 36 out of 61 controllers in a letter to management demand that this project be stopped for safety reasons. They raise concerns that the procedure has not been fully reviewed and will provoke dangerously close distances between aircraft to the extreme. Whilst global practice is to disentangle departures and approaches, Zurich is doing the opposite. The new procedure would not allow any controller even the slightest margin of lapse or error.

Management reacts by inviting the sceptical controllers to a meeting. By pure coincidence or not: at the same time, a new code of conduct is issued which lists all kinds of repercussions – right up to dismissal. Article 1 of the new code points out that an investigation may be initiated even for “unacceptable conduct causing disharmony within operations”. According to Skyguide, a meeting with Aerocontrol (the controller’s union) results in having demonstrated that “the concerns voiced in the letter have already been taken into consideration and procedures amended accordingly.” Subsequently, half of the signatories to the letter withdraw their concerns, the others quietly fume.


The position of Aerocontrol becomes more transparent in the days immediately leading up to the Überlingen trial. The union tells its members to shut up. “We wish to remind you that any contact with the media is prohibited (….) we prefer a coordinated strategy in dealing with the media, in which we have control over all statements”.


Example 3: Planning gone wrong and its consequences

Skyguide management plan to concentrate the upper sphere of Swiss air space at a new Upper Airspace Centre (UAC) in Geneva, enabling a reduction in personnel and consequential savings. In October 2004, controllers voice concerns, because 30 jobs are to be axed at Zurich before the new UAC is even opened. The controllers have little confidence in the new project on the one hand, and also believe that the job cuts in Zurich will have serious safety implications if the UAC project cannot be implemented as planned.

The protest by controllers has little effect on Skyguide’s management. However, an anonymous letter is sent to Federal Councillor Mortiz Leuenberger, whose portfolio includes civil aviation. The letter, sent in January 2006, points to “mismanagement and a continuous string of wrong decisions which cause grave concern to its authors”. The writing controllers criticize what they term a “cost intensive and useless exercise” and point to safety issues. “Skyguide cannot afford a second Überlingen”.

Indeed: two days before it is to go online, Bazl intervenes and pulls the plug on UAC, stating that the system is neither fail-safe nor properly tested. In addition, there appears to be any proof of proper training of controllers. In general, Skyguide is accused of awarding sufficient priority to safety. As a direct result of the collapse of the UAC project, there are now only 165 air traffic controllers at Zurich (instead of 206). This blatant shortage can only increase the risk of errors.


Example 4: Firings

Two of the authors of the letter of 10th March 2002 (“it is hard to imagine that we shall get through summer without trouble”) are women. As supervisors of assistant controllers they have often criticized shortcomings in safety and management, for instance in the context of the UAC and of non-adherence to duty rules.

In September 2005, one of the women receives the shocking news from her physician that she is suffering from leukaemia; six months later, Skyguide fires her after 27 years of service and excellent qualifications, citing that she had repeatedly acted without loyalty and against the interests of the Company. Her colleague is fired under the same pretext.

Both women go to court, and the verdict by the Bülach District Court (the same court with jurisdiction over the Überlingen mid-air collision case) is expected this autumn. Skyguide says that the two firings have to be seen against the background of “other issues, which we cannot make public for legal reasons.”

During the Überlingen trial, Prosecutor Bernhard Hecht tore into Skyguide for its “deficient awareness of risk” at management level and its “climate of carelessness” at operations level. Management clearly saw a greater priority in efficiency – read “profit” – than in safety. He called Skyguide’s management poor role models, being “careless, uncritical and uncommunicative.”

Skyguide, however, point out that Bazl are far stricter and more rigorous in any international comparison. In view of the number of aviation accidents in recent Swiss transport history this could be understood and seen as reasonable. But, says Skyguide, the logical consequence of this change in policy means, “that we have to find the common ground between us again”.

[ATC Watcher]

Nothing new in this article , but one can can only wonder as to why this article appears only 3 days before the verdict of the Ueberlingen trial is going to be made public...

[ettore]

There is nothing such as a Collision Avoidance System betwenn Newsmen and Judges. But, knowing the judicial system in Switzerland, you can rely on that its decision won't be influenced by a press report. Remains the public: so far, it didn't really took into account SkyGuide mismanagement before getting to the airport... :ouch:

[amanoffewwords]

4 ATC managers have been convicted according to the BBC newsflash I just saw. No more info at present.

[ATC Watcher]

Awaiting the details , but the TSR ( swiss news agency ) reported 4 of the 8 condemned , 4 others acquitted.
The 4 condemned are reported to be 3 management staff each received 12 months jail suspended sentences and the maintenance chief is condemned to 90 days-fine of 150 CHF each ( Swiss fine system ).
More later

[ORAC]

BBC: Four guilty over Swiss air crash (http://news.bbc.co.uk/2/hi/europe/6977136.stm)

A Swiss court has found four employees of an air traffic control firm guilty of manslaughter over the deaths of 71 people in a mid-air collision in 2002.

Three of the four managers convicted were given suspended prison terms and the fourth was ordered to pay a fine. Another four employees of the Skyguide firm were cleared of any wrongdoing.

Prosecutors had said a "culture of negligence" at the firm contributed to the mid-air collision, which killed mostly Russian children.

[mjtibbs]

The BBC should correct thier news flash.

The flash says (as of 3:45GMT) "4 ATC Controllers convicted..." but the story clearly states that they were actually management staff.

[Packsonflight]

As I recall, the part of the system that warns the controller if two ac are on a collision track where not operational this terrible night. and because of that two controllers instead of one where on duty
I was wandering if some controllers used this part of the system as a reminder for them selves of when to issue a climb or descent order to ac.
If that is the case it increases the risk of forgetting to take action if the controller is used to act on the "warning."

[ORAC]

Additions to the BBC report:

............All eight men on trial had maintained their innocence. Seven had continued working for Skyguide until the time of the verdict.

The BBC's Imogen Foulkes, in Berne, says it is significant that the four Skyguide employees acquitted were all air traffic controllers - rather than managers. She says this shows the judges backed the prosecution's view that the managers at Skyguide were responsible for introducing negligent, potentially dangerous working practices.

Two separate investigations have already found what were described as organisational deficiencies within Skyguide. These deficiencies were said to have contributed to the accident........

[Tarq57]

As I recall, the part of the system that warns the controller if two ac are on a collision track where not operational this terrible night. and because of that two controllers instead of one where on duty
Yes, and no. One controller was handling two sectors. In addition to the conflict alert being withdrawn, aspects of the communications system were down for maintenance. I believe the two sectors were adjacent, ie, unable to be configured to configured to operate from one workstation.
I was wandering if some controllers used this part of the system as a reminder for them selves of when to issue a climb or descent order to ac
Absolutely not. The system operates by issuing a warning when it calculates the space between the aircraft is about to become inadequate. It's an "on/off" thing. Nobody would operate in this fashion. It's to controllers what TCAS is to pilots, a safety net.

[KiloKilo]

When reading the article at CNN.com (http://www.cnn.com/2007/WORLD/europe/09/04/swiss.air.ap/index.html) at the end they state;

He also mistakenly told the Russian plane to descend -- sending it straight into the cargo jet.

Rather debateble. Not the fact that it was wrong. But that it indeed was a mistake fully by the controller.

[songbird29]

For Ppruners mastering German the following link gives a comprehensive report of the trial and the verdict:
http://www.nzz.ch/2005/10/30/il/articleD9VFI.html
Main points:
The one-man operation as applied in Zurich is not in accordance with safety requirements in Air Traffic Services. The organisation of ATC requires a backup for human failure.
Three managers, between 50 and 61 of age, one of them being the former manager of ATC Zurich, were found guilty for negligent behaviour resulting in the death of people and sentenced to 12 months suspended.
The Swiss one-man operation had been contested previous to the collision and had been suspended in Genève. In Zurich nothing had been changed despite repeated criticism, which the court noted as "industrial blindness".
The lack of information about the maintenance of communication lines was blamed to the project leader, who was on leave at the time of the collision but had failed to inform the adjacent centres; The 64 years old pensioned project leader was sentenced to a fine of 13.500 Swiss Franks. The technician on duty at the night of the collision was acquitted.
Also acquitted was a supervisor, a system manager and the controller who had taken a rest. The latter was acquitted thanks to a juridical contradiction. On the one hand he was charged to be negligent in obtaining information about his watch but on the other hand he had taken his rest despite this knowledge and in agreement with his (murdered) colleague.
Skyguide is discussing with their convicted staff whether to lodge an appeal. Two of the convicted staff are still employed, but not in their original function. The court called the convicted staff members to accept their conviction in the interest of all parties involved.

[PBL]

CNN:
He also mistakenly told the Russian plane to descend -- sending it straight into the cargo jet.

Rather debateble.

Not at all debatable. As you imply. It wasn't a mistake.

Giving an aircraft in a conflict situation a clearance which will resolve that situation is absolutely the right thing to do. The only procedural exception is when the controller *knows* that an aircraft is operating under an ACAS RA, in which case heshe is to issue at most informational advisories only.

(It should be clear that I am not going to follow ATC Watcher's plea not to re-open the discussion of the accident. I beg forgiveness. From the comments so far, it seems to me that there is certain information about TCAS that has not made it out into the wider pilot community and I think it might be opportune to point to it here.)

Nielsen was not advised of the RA until some half-minute into the situation, because DHL's FO was in the loo and the CAP was concentrating on his flight duties.

Nielsen undertook two actions which one can characterise as mistaken. One was allowing the loss of required horizontal separation. The other was in reporting the conflicting traffic to Bakshirian at 2 o'clock when the traffic was actually at 10 o'clock and in sight. (I am not going to address here the causes of these actions. These have been well laid out elsewhere.)

This latter turned out to be crucial. As I speculated in a WWW-available paper a month after the collision, and which was confirmed by the report, this led the Bakshirian crew to think they were in a three-aircraft conflict situation: themselves, traffic at 10 o'clock in sight, and further traffic at 2 o'clock that they didn't see. As I argued in my paper
in the 2004 Safety-Critical Systems and Software conference in Australia, available at
crpit.com/Vol47.html (http://crpit.com/Vol47.html)
alternatively at
http://http://www.rvs.uni-bielefeld.de/publications/Reports/SCSS04.pdf (http://www.rvs.uni-bielefeld.de/publications/Reports/SCSS04.pdf)
this presented Bakshirian with a decision situation in which it was rational for them to choose to descend.

There are two crucial observations which follow from this, which have unfortunately been lost in the ensuing chatter.

1. Despite the "TCAS philosophy" which says that
TCAS activates when aircraft have violated separation; andtherefore when ATC has already failed; and therefore ATC is "out of the reckoning",
it is still possible for ATC to give legitimate input which will causally influence the outcome of an avoidance manoeuvre. In other words, the "TCAS philosophy" is based on a mistake.

When I say "legitimate", this does not mean "non-mistaken". People do make mistakes; indeed, the cognitive mistake made by Nielsen in his statement is common ("2 o'clock" is the participant-reciprocal of "10 o'clock). A system design which relies for its efficacy on operator actions, and TCAS is such, must explicitly take into account such common forms of human error.

2. One might also think that, had Nielsen known of the RA sooner, the outcome would have been avoided. Not necessarily so: it would have been within ICAO guidelines for Nielsen to have said "Bakshirian, advise intruder at your 2 o'clock" even if he knew of the RA, thus putting the Russians in exactly the same decision situation as they had in the actual scenario.

It is well known that a two-aircraft resolution algorithm such as employed by TCAS cannot resolve all conflicts. However, it is not even known whether the algorithm can even resolve all *three-aircraft* conflicts. (Is it known through work of Nancy Lynch and colleagues at MIT that it can resolve all two-aircraft conflicts.) Since 2002, I have offered a PhD to anyone who can either show that the TCAS algorithm mathematically resolves all three-aircraft conflicts, or alternatively produce a three-aircraft scenario which it cannot resolve (I have reduced the choice of such a scenario to a limited set of cases). Five years later, no one has successfully taken up that challenge. It stands; I issue it again here.

I cannot think it wise to advise people to *always, without exception* follow an RA, when we don't even know that the algorithm is correct (that is, correctly resolves all cases that concern us, such as three-aircraft conflicts), unless a risk analysis has been performed to show that the exceptions are expected to occur in only a negligible number of cases. To my knowledge, no such analysis has ever been performed.

I think it even less wise to suggest *mandating* the following of an RA, as the BFU issued as a safety recommendation. Forcing people to follow an algorithm which you can't show is correct is not something which sits well with modern ideas of society and choice. (BTW, I don't know that the BFU was aware of the issues I mention here at the time they issued their recommendation. But they could have been: I put the info on the WWW in August 2002.)

PBL

[radicalrabit]

(30 years since I was at Leeming as an air ftaffic control assistant) .
It is always tragic that people fix on a course of action and die but surely a simple solution would have been if both aircraft had turned left even for a few seconds then they would have each headed away from the other? The problem was surely they were both heading for the same piece of airspace and they needed to just not do that. A few seconds then back onto their headings with danger passed? Tell me why they couldnt have done that ? Isnt the decision to focus on the decent or climb rather than change heading the key factor here?:oh:

[songbird29]

And for French reading Ppruners I recommend: http://www.letemps.ch/template/regions.asp?page=7&article=214204

This article in the Geneva based 'Le Temps' is even more outspoken than the German language paper of Zurich cited in my previous message.
In an editorial it is commented that an entire industrial culture has been sanctioned. For years on end Skyguide Directors had tolerated that a single controller handled the traffic, while only on paper a second one was attributed who was in fact paid for taking his rest in another room. The responsible managers had forgotten that safety is all about taking account of the unforseen and the possibility of human error.
That is the reason why the managers in their offices now foot the bill by getting severe punishment. Whereas THE FRONT-LINE EMPLOYEES HAVE QUITE CLEARLY BEEN DISCHARGED. The president of the tribunal has taken the occasion to REHABILITATE THE LATE DANISH CONTROLLER ON DUTY on the night of the tragedy, whereas his colleagues had the delicacy of putting all the blame on him.
Although the verdict is against individuals, Skyguide as an enterprise is at stake. The woolly reaction on the verdict by Skyguide will not improve anything. Their new director will have a job in restoring confidence.

So far the commentary of this newspaper, confirming that our colleague Peter Nielsen has been rehabilitated. The confidence in Skyguide as an organisation may be low, my confidence in the Swiss courts is very, very high.

Songbird

[PBL]

surely a simple solution would have been if both aircraft had turned left even for a few seconds then they would have each headed away from the other? .......... Tell me why they couldnt have done that ?

There has been quite a considerable amount of research done on 3-dimensional collision avoidance algorithms.

Contrary to what you say, it is not simple.

Every collision could be avoided by some simple manoeuvre. The trick is to devise a simple manouvre which will avoid every collision, without introducing more dangers than it solves.

PBL

[Atishoo]

What happened to Mr Neilson?

[Tarq57]

What happened to Mr Neilson?
He was stabbed to death at his house by a relative whose family died in the TU154.
That man is currently serving a prison centre.
Mr Neilsen has been...I don't remember the exact word, but it amounts to exonerated,or absolved, more or less, at the recent legal proceedings.

Shame the world's media didn't follow up on the original story. Immediately after the crash, the media pretty much fingered Peter Nielsen as responsible. By the time it was starting to become clear that (of course) it was a little more complex than that, I guess the news was too boring for them.
Not that it would have made much difference, I guess. The poor relative was probably half crazy with grief by then, anyway.

But it might have.

[Frangible]

I differ with PBL on the likely causes of the Bashkirian crew’s decision to descend. My reading of the translation of the CVR is that they were in a simple dilemma about whether or not to obey the controller or TCAS. I don’t see any evidence for worries about two other aircraft in the Russian cockpit in the report or the CVR.

They chose to follow the controller instead of TCAS because their training on and experience of TCAS was very limited, and also because their manuals stated that a TCAS RA was a “recommendation” to the crew, not an absolute requirement. On the CVR the Russians don’t mention two other aircraft and when they see the DHL they only ever talk about “it”.

I don’t see how PBL can argue that the 10 o’clock versus 2 o’clock confusion was “crucial”. He says nothing to contradict the more obvious interpretation, which is that they were conflicted about what to do and made a bad choice.

PBL’s point 1 is strange. Is this really the TCAS “philosophy”? If that is printed somewhere, I would like to see it, as it seems a strange and illogical assertion for software experts to make. They are only dealing with their own system. ATC is another system. Where the designers, regulators and ICAO failed was in not emphasising strongly enough the dangers that would arise when both systems issued different orders to the aircraft at the same time.

As ATC Watcher pointed out before, when you translate the American “advisory” into other languages it often does not come out, as it should, as “command”. Secondly, there was little acount in TCAS’ implementation of the vital importance of stressing that you must never ever do the opposite of a TCAS RA. The strictures against this were well buried in the TCAS manual. Now, every pilot has burned into the brain, “Never manoeuvre contrary to an RA”, but before Ueberlingen, less careful airlines with less careful regulators and sketchy training regimes could fail to see the crucial importance of this rule.

I don’t mean to criticise PBL on the software and algorithms front. I haven’t the first notion about them, but I do think that the “three-aircraft scenario”, while of importance to flight safety was never a feature of Ueberlingen.

Finally, to say, as PBL does,

“I cannot think it wise to advise people to *always, without exception* follow an RA..”

is the height of irresponsibility. Perhaps not “follow”, but the golden rule of “Never manoeuvre contrary to an RA” is just that, golden, and to argue otherwise is very dangerous indeed. All sorts of incidents have been recorded where pilots thought their visual intepretation of a TCAS situation was better than the gizmo’s, and they were wrong every time. PBL’s comment is just the kind of thing that could possibly introduce doubt in the minds of pilots.

[visibility3miles]

What happened to Mr Neilson?

There was a thread about it when the person was sentenced for killing the controller:
http://www.pprune.org/forums/showthread.php?t=195886

[RatherBeFlying]

Les trois cadres devront participer aux frais de justice et payer un dédommagement aux proches des victimes. Quant au chef de projet qui avait coordonné les travaux d'entretien, en vacances la nuit du drame, il doit, également reconnu coupable, payer son manque de communication, entre autres auprès des centres de contrôle étrangers.My first impression was that a suspended jail sentence does not count for much, but it looks like they're getting a severe kick in the wallet:ouch:

[PBL]

I differ with PBL on the likely causes of the Bashkirian crew’s decision to descend.


I didn't say it was a likely cause. I said it was a rational choice.


I don’t see any evidence for worries about two other aircraft in the Russian cockpit in the report or the CVR.

I take it you didn't yet check Section 2.2.2 of the (english version of the) report, which says "According to CVR data it can be concluded that the instructor searched the airspace in front and to the right in vain."

PBL’s point 1 is strange. Is this really the TCAS “philosophy”? If that is printed somewhere, I would like to see it

For example, see Section 2.1, The Functional Requirement of Ed William's paper at
crpit.com/Vol47.html (http://crpit.com/Vol47.html)
I quote:
TCAS is a system of last resort and hence should have the following characteristics:
* Should only intervene when all "normal" means of separation have failed
........
* Should have minimal reliance on other systems
...

Section 2.2 elucidates the meanings of "normal" means and other systems.
My observation that ATC is considered to be "out of the picture" follows from this second stated requirement.

Finally, to say, as PBL does,
“I cannot think it wise to advise people to *always, without exception* follow an RA..”
is the height of irresponsibility.


Let me invent an acronym, HoI. People like to say "HoI this" and "HoI that" when talking about collision avoidance, as a way of trying to say they are worried about something. Well, it's good to be worried about something as important as collision avoidance, but it is not necessarily helpful to resort
to moral judgements in advance of having understood the technical claims.

Frangible, do you consider it HoI not to do a risk analysis on the situation of TCAS failing to resolve a conflict? Do you consider it HoI not to analyse the possible causal interactions between controller information and RAs?
If not (for extra credit :) ), why not?


All sorts of incidents have been recorded where pilots thought their visual intepretation of a TCAS situation was better than the gizmo’s, and they were wrong every time.


I infer that you know of lots of midair collisions in which pilots did not follow their TCAS advisory. I only know one.

If you think that pilots should always, without exception, follow the RA, would you change your mind if it turned out that the risk was relatively high that the TCAS algorithm could not resolve a given three-airplane conflict? If not (again, for extra credit), why not?

PBL

[Spuds McKenzie]

TCAS is a last resort tool, nothing more, nothing less.
If you use it correctly you're fine, if you don't, you're either lucky (like the DC10 and B747 crews over Japan on 31 January 2001, which missed each other by an estimated 60 meters, after, and this is very interesting, one of the crews decided to follow ATC instruction instead of TCAS) or you're not (like over Überlingen).

Fact is, if TCAS had not existed on 1 July 2002, there wouldn't have been a collision (the 757 would have maintained level, the TU154 would have flown underneath in descent as instructed).
So, since TCAS did exist, what would be the conclusion...

[PBL]

Fact is, if TCAS had not existed on 1 July 2002, there wouldn't have been a collision

Yes. I am very glad to see that this straightforward observation is now becoming common currency.

Fact is that, had TCAS been available since 1950, it would have helped avoid four collisions in 36 years (Grand Canyon, Zagreb, San Diego, Cerritos). Since it was mandated (a matter of some 16 years in the U.S., less elswhere), use of TCAS has almost caused two collisions (Albany, NY, 1998, another three-aircraft situation; 28 June 1999 in Chinese airspace between BA027 and KE507) and been a contributory factor in one accident (Überlingen, as you point out). And that's just what I know about. Interestingly, the potential outcome at Albany was ameliorated through intervention of a controller, just the opposite of what is "supposed" to happen.

So, 4 in 36 years against 3 in 16 years. These figures are too sparse to draw any statistical conclusions. But they should suffice to indicate that the risk analysis is not at all obvious.

PBL

[Frangible]

Your first point. It may well have been a “rational choice”, but there is no evidence it is the one the Russians took, so you are only confusing matters by calling it “crucial”.

Your second point. If the instructor searched in vain, it does not mean he or the crew were confused, especially as they did not discuss it. It is entirely possible the instructor searched, found nothing, and concluded there was only one plane. However, they did debate whether to follow TCAS or ATC.

You are introducing the possibility of confusion by fastening on a speculative case rather than the actual, accepted case.

Your third point in fact supports my own. Your citation from the specs is undoubtedly correct, but banal. No TCAS design could possibly account for a factor completely extraneous to it, e.g. a controller getting on the horn and telling the crew to do the opposite of the TCAS instruction. It was the responsibility of the managers and regulators of air traffic control generally to demarcate the respective responsibilities of the controller and TCAS in all situations, and they failed to do that unambiguously.

If you say no “three-way” risk analysis has been performed then I would have to take your word for it, and maybe agree that it should be done if it hasn’t yet. I somehow doubt, however, that the risks here are not understood and have been ignored.

As for your final point about me possibly being aware of other midair collisions, you being only aware of one, I spoke of incidents only. The ACAS II bulletins have published case studies of TCAS encounters for several years.

One example was a 146 pilot who ignored his TCAS RA because the high angle of attack of the 747 he had visually acquired fooled him into believing it was climbing, when it was in fact descending. The result was a serious loss of separation. Same thing happened with the JAL 747 and the JAL DC10 over Japan when a pilot thought his visual information was superior to the TCAS RA. They missed by 10 metres.

I know that Eurocontrol carried out a large study of incidents involving non-compliance with TCAS and found other worrying incidents after Ueberlingen but they did not publish them because the study was done in co-operation with one particular airline under conditions of confidentiality (understandably).

I simply suggest that there have been rare cases where pilots thought they knew better than TCAS, and your remarks could encourage that tendency.

And you, incidentally, will acquire lots more credit if you drop the sarcasm.

[PBL]

Your first point. It may well have been a “rational choice”, but there is no evidence it is the one the Russians took,


Correct.


so you are only confusing matters by calling it “crucial”.


To date (five years), only a couple people have been confused.


Your second point. If the instructor searched in vain, it does not mean he or the crew were confused, especially as they did not discuss it.


He was the commander of the airplane. If he is looking for it, it means he thinks it might be there. If he thinks it might be there, it is reasonable to assume it will enter his decision-making (recall, he made the decision to continue to descend, against the query of the PF).

But you are right, and I emphasise again, that I am not attempting to *explain the actual decision*, merely to point out that it is a rational decision-theoretic choice.


You are introducing the possibility of confusion by fastening on a speculative case rather than the actual, accepted case.


I am analysing a specific scenario which is very, very close to the Überlingen scenario, if not identical with it.

This is exactly what hazard analysts do. This is what the laws of most countries require to be done before any piece of safety-related digital equipment such as TCAS is introduced into use.

If that introduces the "possibility of confusion", then so be it.


No TCAS design could possibly account for a factor completely extraneous to it, e.g. a controller getting on the horn and telling the crew to do the opposite of the TCAS instruction.


Now, you see, I don't believe that.

Hazard analysis *has to* account for factors completely extraneous to systems. That is what hazard analysis is.


It was the responsibility of the managers and regulators of air traffic control generally to demarcate the respective responsibilities of the controller and TCAS in all situations, and they failed to do that unambiguously.


Well, yes, but that is a separate issue. BTW, that demarcation is still ambiguous, and will remain so for the foreseeable future.


I somehow doubt, however, that the risks here are not understood and have been ignored.


On what basis do you doubt it?


I spoke of incidents only [rather than collisions].


I see. Maybe it wasn't clear to me what you were meaning to say. You said

.... incidents ...... where pilots thought their visual intepretation of a TCAS situation was better than the gizmo’s, and they were wrong every time.


You explain now:


I simply suggest that there have been rare cases where pilots thought they knew better than TCAS, and your remarks could encourage that tendency.


Well, you see, it is that "every time" that is problematic. There are a number of incidents in which the human interpretation was *in fact* better than that of TCAS.


you, incidentally, will acquire lots more credit if you drop the sarcasm.

Sorry you took it badly. I was trying to be humorous. I don't need the credit, thanks (or even the extra credit....).

Could you maybe actually answer the questions that the smileys were attached to? There is a reason I asked them.

PBL

[Frangible]

If you are really saying there are as many, or more, instances under TCAS version 7 where pilots’ instincts were right and the TCAS wrong, then we had all better stop flying right away.
It is axiomatic that with no TCAS, there would have been no collision. Equally, however, if there had been no ATC, and TCAS only, there would have been no collision. This is my point about demarcation – mix up the boundaries and you court disaster.
I suppose I reacted at first against some of what you were saying because it was by no means clear to me that you were using Ueberlingen as template onto which to put speculative scenarios. Now I see that, this debate becomes less interesting to me. You can call it simplistic, but I am in favour of preventing recurrences of that tragedy, and I don’t see how “decision-theoretics” are helping.
My bottom line, on which I will sign out on this palaver, is simply that you should not go around saying it is unwise to advise pilots always to follow the RA. If pilots fly contrary to the RAs, then TCAS becomes the cause of collisions and completely useless.

[Spitoon]

Fact is that, had TCAS been available since 1950, it would have helped avoid four collisions in 36 years (Grand Canyon, Zagreb, San Diego, Cerritos). Since it was mandated (a matter of some 16 years in the U.S., less elswhere), use of TCAS has almost caused two collisions (Albany, NY, 1998, another three-aircraft situation; 28 June 1999 in Chinese airspace between BA027 and KE507) and been a contributory factor in one accident (Überlingen, as you point out). And that's just what I know about. Interestingly, the potential outcome at Albany was ameliorated through intervention of a controller, just the opposite of what is "supposed" to happen.

So, 4 in 36 years against 3 in 16 years. These figures are too sparse to draw any statistical conclusions. But they should suffice to indicate that the risk analysis is not at all obvious.
This is a rather simplistic analysis of the situation and it is at least reassuring that PBL does not try to draw any statistically based conclusions, albeit only for one of many reasons.

The reality is that the environment has changed significantly since 1950 and what may have happened then is not necessarily any indication of what might happen now or in the future (something that hazard analysts should think about). How much more traffic is around today compared to the 1950s? And how much have air traffic services changed? And how much have flightdecks changed? And the the operating procedures for modern aircraft? Making claims based on historical data in such a rapidly evolving environment is not for the faint-hearted!

Likewise, PBL's statistics are based on a sub-set of events in which TCAS may play a part. How many near misses occurred over the 36 years but were nothing more because of good fortune? And how many have been avoided in the 16 years because of increased situational awareness(although the accuracy of the information propvided by TCAS in this respect is often misunderstood) on the flightdeck?

Like so many other systems that we use today, TCAS provides benefits and creates hazards that would not otherwise have existed. Hazard analysis can help us to understand ways of managing risks - but it's not the panacea that some appear to think it is. It certainly doesn't guarantee that things won't be missed, that hazards won't evolve since the last analysis activity, or that the system will be used in the way that was originally intended.

The fact is that TCAS is here. With TCAS and countless other newly developed or evolving systems, we should learn lessons from previous (sadly sometimes tragic) experience. We should use it in the most effective way possible rather than trying to highlight supposed weaknesses and imply that this makes it a 'bad thing'.

By way of brief example,

[PBL]

This is a rather simplistic analysis of the situation


Oh, good heavens, that isn't an analysis. It is a simple statement of fact.

I advise you to be careful of words like "simplistic". They can come back to bite you.


Making claims based on historical data in such a rapidly evolving environment is not for the faint-hearted!


Indeed so. And so is making claims based on the ideas someone had of what is a close call. But that is all the data one has for judging whether TCAS is a net benefit or not.
The point being that judging whether TCAS is a good idea or not is not a data-based decision, as Frangible was suggesting it was.

The fact is that TCAS is here. .... We should use it in the most effective way possible rather than trying to highlight supposed weaknesses and imply that this makes it a 'bad thing'.


Ah, that word "simplistic" comes to mind, along with "straw man".

I said that necessary analysis was missing. And I said that, if I may paraphrase myself, I consider it unwise to go gung-ho-exceptionless for a technology unless the necessary analysis is there to support that decision.

PBL

[PBL]

....... with no TCAS, there would have been no collision. Equally, however, if there had been no ATC, and TCAS only, there would have been no collision.


Both correct. (I omitted the word "axiomatic" since I am unsure what you mean by it.)


This is my point about demarcation – mix up the boundaries and you court disaster.


Now that is an interesting, and likely mistaken, viewpoint.

Boundaries between systems *are* mixed. It is necessary, indeed essential, to study the interactions. And as far as I can tell, that has not been done analytically with TCAS and ATC.

The Eurocontrol ACASA project did a bunch of simulations and analysed them thoroughly, but they did that with about two days' worth of actual data. Unfortunately people have drawn conclusions from that data about system interactions which claim to reach accuracies of one event in O(10**9) operational hours, which mathematically speaking one cannot justify from that limited data. Great project, but there seems to be a human tendency to claim what senior management wants you to claim, rather than to claim what your data support. That is why I like hazard analysis.

Similar happened with the Space Shuttle. Feynman's appendix on risk and hazard analysis to the Challenger report, cited on the Okinawa thread, makes a good read on that topic.


it was by no means clear to me that you were using Ueberlingen as template onto which to put speculative scenarios. Now I see that, this debate becomes less interesting to me. ...... I don’t see how “decision-theoretics” are helping.


Shame. But each to his own. I just wish that more professionals understood how hazard analysis works.


...... you should not go around saying it is unwise to advise pilots always to follow the RA.

It seems to me you are not quite reading what I said. See my reply to Spitoon.

PBL

[Spitoon]

PBL, phrases like 'use of TCAS has almost caused two collisions' and 'he potential outcome at Albany was ameliorated through intervention of a controller' suggest to me that you are reading something into facts (based largely, I presume, on the occurrence investigation reports) - I've always called this analysis and, in this case, it's simplistic. FWIW, I don't equate simplistic with bad, I just like to be aware of the assumptions and aproximations that have been made. Just to be absolutely clear, a statement of fact would be that two aircraft that were within a specific distance of each other generated a TA or RA. The problem with any quantitative analysis designed to assess TCAS effectiveness, or for that matter, the probability of occurrence of some identified failure mode, is that there is no complete data set and thus some assumptions must inevitably made.

The point being that judging whether TCAS is a good idea or not is not a data-based decision, as Frangible was suggesting it was.If it is not data-based to the extent that the data can be relied upon, and I accept that we could have a lengthy debate about pass/fail criteria etc., what would you base the decision on?

Ah, that word "simplistic" comes to mind, along with "straw man". Sadly, I think it must be my simplicity but I don't understand your point. All I was saying was that TCAS exists now, just as today's traffic levels exist, and whatever else you might want to cite in the environment in which we operate, and we have to use it as effectively as possible. In order to do so we have to analyse everything we know about it in the best way that we know how. I wasn't suggesting any gung-hoing!

But if I might end with a slightly contentious thought, one of the 'problems' with TCAS was the unilateral way that it was introduced without consideration of the system totality and, if I recall correctly, in a knee-jerk reaction to a mid-air collision. And we are still trying to fix the problems that this created. As I say, we should learn from the past, but it seems to me that, in some respects at least, contemporarily we are seeing a similar course of events over another safety net system, that designed to address runway incursions and the associated risks.

[PBL]

But if I might end with a slightly contentious thought, one of the 'problems' with TCAS was the unilateral way that it was introduced without consideration of the system totality and, if I recall correctly, in a knee-jerk reaction to a mid-air collision. And we are still trying to fix the problems that this created.


I see we agree on the essentials. My main point is that necessary analysis has still not been done.

it seems to me that, in some respects at least, contemporarily we are seeing a similar course of events over another safety net system, that designed to address runway incursions and the associated risks.

I don't know enough about that system yet to draw any conclusions. I hope that a similar high-visibility accident does not lead to a similar mandated-intro until the system has been thoroughly analysed.

PBL

[EUROSPIRO]

Even after Uberlingen and all that Eurocontrol and the EU have done for safety and the implementation of Safety Management Systems, most continental center/airports are only paying lip service to safety management. Where NATS takes safety seriously, appointing a Safety Director, there is no ANSP on the continent who does the same. Safety management is present, but buried in processes and in some cases the safety managers are responsible to line managers!!! Wake up Europe and give safety the priority it deserves and start leading from the top, before it happens again. Even the Eurocontrol ATC center in Maastricht does not have a Safety Director at the highest level of management.

[N380UA]

EUROSPIRO; not correct I know for a fact that Skyguide (of all) does have a safety director which reports directly to the board of executives and has the power to assemble the board of directors if necessary.

[EUROSPIRO]

Well there is one that has learn't the lesson ... :D

[Brian Abraham]

From Avweb today

Four Swiss Controllers Convicted of Manslaughter
In the continuing fallout from a 2002 midair collision in Swiss-controlled airspace in which 71 people died, four air traffic control managers on Wednesday were convicted of manslaughter, Reuters reported. The judge said the managers were responsible for ensuring that at least two controllers were on duty at all times, and the collision could have been averted if any one of them had acted to prevent the second controller on duty from taking a coffee break. That left just one controller working at the time of the collision. The lone controller was later killed by a Russian man who lost his wife and two children in the crash. The four managers, who are employees of SkyGuide, an air-traffic company, were given suspended prison terms and fines. Francis Schubert, Skyguide's interim CEO, said the company has "learned the lessons from this tragic event and has done everything to ensure that an accident of this kind cannot happen again."

[Tarq57]

Four Swiss Controllers Convicted of Manslaughter
Controllers indeed. Snitty note sent to AVweb.
One expects this from the "regular" media, such as Reuters, not from AVweb.:mad:

[26left]

Would appreciate help with: how/when I can get access to an english version of the trial judgement. Need to study the possible implication for ATS staff and providers.
Thanks

[Al Fakhem]

Songbird:

"The confidence in Skyguide as an organisation may be low, my confidence in the Swiss courts is very, very high."

I suspect you might not have been following the "Swissair" trial, then?

[joernstu]

@radicalrabit

It is always tragic that people fix on a course of action and die but surely a simple solution would have been if both aircraft had turned left even for a few seconds then they would have each headed away from the other?A change in course by both aircraft may well have prevented the collision, but not necessarily so. The Ueberlingen collision itself can (in part) be taken as an example for this:
The TU154M e.g. did change its heading twice prior to the collison. Once to the left, then to the right. This can be seen on the reconstructed flightpaths in Appendix 1 of the accident report and is mentioned in the report.

Interestingly enough, the cause of the second change in the TU154M heading is not explained in the investigation report (at least I was not able to find it).

[joernstu]

@Fangible

If TCAS is treated as such an important device that its advisories are never to be contradicted, one would ask, why TCAS is not redundant on aircraft and why it was (is?) possible to operate an aircraft for up to 10 days with TCAS failure.

As Brazil (Gol/ExcelAire) has shown, TCAS only works with operational TCAS devices on both aircraft.

[ATC Watcher]

If TCAS is treated as such an important device that its advisories are never to be contradicted, one would ask, why TCAS is not redundant on aircraft and why it was (is?) possible to operate an aircraft for up to 10 days with TCAS failure.


Redundant : TCAS is a last minute device , that cannot be used to determine target levels of safety.Also too expensive ,well over 100.000 USD per unit .

10 days : Too long , we all agree and some would even like this on the MEL. But strong opposition from Airlines .




I have opened a separate Thread on TCAS to continue this interesting discussion , but which is outside the Ueberlingen Trial.

One of the main points for us in this trial is that Peter Nielsen has been rehabilitated by the Judges. That is good news send around by the Judiciary. For once : :D

[carpediem86]

hey we are law students participating in an international law moot court competition. We happen to have a case identical to that of the ueberlingen collision (same facts just made up countries and services) and we are so lost in all the terminology about ATC and TCAS and STCA etc etc. If someone could help us out with a few clarifications it would be greatly appreciated. One more thing, what is the difference between ATM and ATC? I mean, does ATC fall into the sphere of ATM? Cause we are reading the ESARRs and they keep talking about ATM while in our case the company that is like skyguide was providing ATC services? Thank you so much all in advance and anyone who could possibly help and is willing to, are welcome to send us a private message :)

[Dream Land]

My guess is that ATM is similar to a business strategy that companies like Skyguide employ to provide an adequate, safe, and profitable service. The definition of ATC is the day to day services provided by air traffic controllers from facilities called ARTCC's, Towers, and Approach controls.

[ATC Watcher]

carpediem . A bit complex to explain ATC in 10 lines .It takes a good year of training for a controller to get throught the stuff.
Short version :
ATM is Air traffic Management , it comprises Air traffic Flow management (ATFM) and Air traffic services (ATS) which itself contains Air traffic control ATC, plus the Weather services (MET) and Search and rescue (SAR).

ACAS is ICAO generic name for TCAS which is a brand name, it is airborne collision Avoiding system, An airborne system providing resolutions advisories (RAs) to pilots aimed at preventing a collision.

STCA is Short term conflict alert , a ground based ( i.e for ATC) system warning controllers when aircraft are on collision course and are about to loose separation ( normally 5NM and 1000 ft )