Sky-crashGuide report released
Joined: Nov 1999
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From: South East UK
There's a fairly ironic fact buried deep down on page 61.
Although the two aircraft were both at FL360 initially, their altitudes were 50ft apart.
Might just have been enough for them to miss each other if they hadn't done anything at all.
Although the two aircraft were both at FL360 initially, their altitudes were 50ft apart.
Might just have been enough for them to miss each other if they hadn't done anything at all.
Joined: May 2003
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From: Sarf England
An interesting and harrowing report. What I took from it was that the ATCO concerned was a fairly minor link in a horrifying chain of coincidental events that led to the disaster. Any one of a number of things could have broken that chain, but there are two which stick in my mind.
[list=1]The Russian Crew were trained, effectively, to follow an ATC clearance if an occasion arose where ATC and TCAS gave conflicting instructions, as is evidenced by the following:
"For the avoidance of in-flight collisions is the visual control of the situation in the airspace by the crew and the correct execution of all instructions issued by ATC to be viewed as the most important tool. TCAS is an additional instrument which ensures the timely determination of oncoming traffic, the classification of the risk and, if necessary, planning of an advice for a vertical avoidance manoeuvre."
A very dangerous piece of training when practically the rest of the world knows that TCAS instructions always take precedence over ATC avoiding action if the two are not complementary.[/list=1][list=2]The ATCO was working on two separate consoles, using two separate microphones and two separate radar screens. This would be definitely NOT ALLOWED in the UK under any circumstances, as the ATCO must effectively leave an operational position to use another one. In a word, negligence, but only as a result of bad management. If two ATCOs had been on duty, the conflict would have been seen much earlier and would have been a non-event.[/list=2]
airship
Why? Because this instruction would just happen to be in agreement with the RA that the 757's TCAS was issuing? What I'm trying to say is, it was a 50/50 chance that just became another link in the chain. Controllers have many skills, but clairvoyance is not one of them. The ATCO chose to descend the TU-154 because, as has been mentioned, it was required to descend for the next part of its journey. The Rules of the Air have no meaning in controlled airspace - I doubt the controller would have considered them in the seconds in which he made his decision.
ShooTheGap
Never mind essential traffic, it should have been avoiding action. I have said on these forums before, and will say again, that best practice for ATCOs SHOULD be to issue avoiding action TURNS if there is any doubt as to whether the aircraft concerned are in a TCAS RA situation. And yet still, two years after Ueberlingen, the recommendation does not appear in the UK Manual of Air Traffic Services. All that appears is the glib statement, "...a controller must not issue control instructions....which are contrary to the RA communicated by the flight crew." Unhelpful at best. Some pilots may take several seconds to report an RA, which is time in which the controller can get himself/herself into trouble. There are any number of controllers, even examiners, who would advocate vertical avoiding action over horizontal, because they have the mistaken belief that it provides the quickest solution. As has been seen, not the case if you're contradicting an RA that you don't know about.
LTP
[list=1]The Russian Crew were trained, effectively, to follow an ATC clearance if an occasion arose where ATC and TCAS gave conflicting instructions, as is evidenced by the following:
"For the avoidance of in-flight collisions is the visual control of the situation in the airspace by the crew and the correct execution of all instructions issued by ATC to be viewed as the most important tool. TCAS is an additional instrument which ensures the timely determination of oncoming traffic, the classification of the risk and, if necessary, planning of an advice for a vertical avoidance manoeuvre."
A very dangerous piece of training when practically the rest of the world knows that TCAS instructions always take precedence over ATC avoiding action if the two are not complementary.[/list=1][list=2]The ATCO was working on two separate consoles, using two separate microphones and two separate radar screens. This would be definitely NOT ALLOWED in the UK under any circumstances, as the ATCO must effectively leave an operational position to use another one. In a word, negligence, but only as a result of bad management. If two ATCOs had been on duty, the conflict would have been seen much earlier and would have been a non-event.[/list=2]
airship
Under the circumstances, if the ATCO had contacted the B757-200 first and instructed them to descend, the outcome would have been just a drama as opposed to a crisis with lethal consequences...
ShooTheGap
what surprises me after reading the report is how with a seperation of 7nm on a scope displaying 80 nm he omits to pass essential traffic to the DHL
LTP
Joined: Oct 2003
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From: Europe
What I can't understand, and I think it wasn't really mentioned before, is - how can you make so self-contradictory SOPs? As was said many times, Russian procedures instructed to follow ATC rather tan TCAS. But other procedures said clearly - maneuvers opposite to TCAS RA are forbidden. So it doesn't really make sense - in the situation they were, you can't do both (follow ATC and not to oppose TCAS RA). I think it might have added to some confusion on their side (decision of PIC to follow ATC, copilots queries about TCAS), adding to little time they had to decide on course of action, and everything coming at the same time.
Per Ardua ad Astraeus
Joined: Mar 2000
Posts: 18,575
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From: UK
criss - there you have it - yet another hole in the famous 'Swiss Cheese' aviation accident model - NB no sick humour intended there.
Life is always full of surprises, not all of them nice, and it is just a terribly sad thing that these things (as with the 'procedures' in place in ATC) only come to light in these tragic circumstances. If you go through any procedures anywhere with a fine tooth-comb it is likely you will find other 'contradictions'. It was the combination of 'holes' there that sadly made this a fatal event. 50-100' difference and there would have been a load of people alive but severely frightened and the holes would have been closed.
The best we can say out of all this is that a few more 'holes' have been shut. I do not mean to sound trite, but it is not a perfect world.
Life is always full of surprises, not all of them nice, and it is just a terribly sad thing that these things (as with the 'procedures' in place in ATC) only come to light in these tragic circumstances. If you go through any procedures anywhere with a fine tooth-comb it is likely you will find other 'contradictions'. It was the combination of 'holes' there that sadly made this a fatal event. 50-100' difference and there would have been a load of people alive but severely frightened and the holes would have been closed.
The best we can say out of all this is that a few more 'holes' have been shut. I do not mean to sound trite, but it is not a perfect world.
Joined: Nov 2000
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lost the picture
Good points well made.
I think from re-reading the posts we are all in agreement that
1. TCAS is a last line of defence.
2. Pilots MUST ALWAYS follow RA advice
3. Controllers MUST give "AVOIDING ACTION" when necessary - and in the horizontal, not vertical plane.
airship
I think we came at opposite sides of the discussion here. I absolutely agree about following procedures and am happy to say that there are very robust ones in place. NATS, Swanwick in particular, has excellent annual Training in Unusual Circumstances and Emergencies (TRUCE).
However in the incident we are talking about, the controller was looking at a different radar display. Therefore, when he looked at the en-route display, it was pretty much already too late.
The picture we see is a 2D plan. In a moment of fear and instinctive action, the aircraft with right of way is not always blatantly obvious. When you are working hard and thinking quickly it is very easy to get your left and right mixed up - particularly when aircraft are moving north to south - I expect the majority of radar controllers here would admit to making the left/right mistake more than once in there careers so far.
The controller made the decision that seemed to be the right one in his mind at the time of the incident. We can not criticise him for that. We can however learn from the result - re: the top of my - points 2 and 3
cheers
Good points well made.
I think from re-reading the posts we are all in agreement that
1. TCAS is a last line of defence.
2. Pilots MUST ALWAYS follow RA advice
3. Controllers MUST give "AVOIDING ACTION" when necessary - and in the horizontal, not vertical plane.
airship
I think we came at opposite sides of the discussion here. I absolutely agree about following procedures and am happy to say that there are very robust ones in place. NATS, Swanwick in particular, has excellent annual Training in Unusual Circumstances and Emergencies (TRUCE).
However in the incident we are talking about, the controller was looking at a different radar display. Therefore, when he looked at the en-route display, it was pretty much already too late.
The picture we see is a 2D plan. In a moment of fear and instinctive action, the aircraft with right of way is not always blatantly obvious. When you are working hard and thinking quickly it is very easy to get your left and right mixed up - particularly when aircraft are moving north to south - I expect the majority of radar controllers here would admit to making the left/right mistake more than once in there careers so far.
The controller made the decision that seemed to be the right one in his mind at the time of the incident. We can not criticise him for that. We can however learn from the result - re: the top of my - points 2 and 3
cheers
Uneasy Pleistocene Leftover
Joined: Feb 2003
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From: Gone, but not forgotten apparently?! All forums marked "Private"...
After reading the BFU report, does anyone else think the TU154M PF got away lightly for disregarding the RA? I hasten to add that I mean this in the sense of apportioning blame in the report only. He has already paid with his life...
Joined: Jun 2001
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From: UTC +8
One helpful technique during any TA is to select the 5-mile range as the target is approaching. This will enhance position orientation in case of an RA. And in case of an RA, while following vertical commands, one might be inclined instinctively to steer away from the approaching target, especially during IMC.
Joined: Nov 2001
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From: uk
Why should the 757 have been descended instead of the 154? If the controller wanted the 154 at the lower level so be it. Rules of the air are rather academic in this environment, fine in VMC. The stress and workload that the ATC guy were under are not exactly unknown, listen to the density of rt in the London zone for instance, sometimes impossible to get a call in for minutes. Reporting a TCAS advisory is not exactly top priority when you are manouvering the aircraft and looking for the conflict. in any case the situation is now out of the controllers hands and happens very quickly, he certainly doesn't have time to coordinate things. An incident of this sort obviously concentrates attention on these particular circumstances but near misses aren't exactly rare and the reason most do not end in disaster is because, in the final analysis, the pilots correctly following the TCAS commands prevent this. Thus the shortcomings that caused them are hidden. The 154 crew may have been confused, the 'spare' FO though seemed to understand the importance of following the TCAS, pity he wasn't PF.
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
I really think we should cease this attempted 'criticism' of anyone here, and take the hard-learned lessons. ATC procedures were inadequate. The TU followed what he understood to be the over-riding of two apparently conflicting 'rules' for his operation.
We gain nothing from trying to apportion further 'blame'? It is obvious that TCAS, if followed by both a/c, would have prevented the accident. The tragic loss of life will, I hope, eliminate any possible confusion over TCAS in the future.
We gain nothing from trying to apportion further 'blame'? It is obvious that TCAS, if followed by both a/c, would have prevented the accident. The tragic loss of life will, I hope, eliminate any possible confusion over TCAS in the future.
Joined: Feb 2003
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From: Old Lyme, Connecticut
"Would it be a good procedure, in a conflict situation, for an ATCO to ask something like this "XXX do you have RA info? follow it , contact me after ..." , prior to give instructions blindly?"
Is there any reason why the system couldn't be engineered automatically to register TAs with local ATC? Is there any practical reason why it shouldn't?
Is there any reason why the system couldn't be engineered automatically to register TAs with local ATC? Is there any practical reason why it shouldn't?
Joined: Jan 2004
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From: Dubai, UAE
Vaneyck,
If I understand your questions properly, then;
When ATC's realize that the aircraft under their control have lost (or are about to lose) separation, the natural course is to take positive action, that is the overriding impulse. To provide "if ... then" instructions is not quite positive enough, because the result is one of two (unknown) possibilities. Sitting down after the fact and considering how it might or should have been handled is not even nearly the same as being there and then, and realizing that these guys are going to get way too close for comfort.
Regarding RA's being passed to the ATC system, IMHO, the problem with that is that the update of the Radar (in conventional systems) is too slow and thus will not be as accurate as the STCA, possibly providing outdated and inaccurate advice.
When this accident happened, there was a pilot that made a statement on these forums, he said that before he did any pre-start checks or anything else, he would say to the other pilot "We agree here and now that when we get an RA, we don't think, we just do it"
Honestly, I cannot think of any better advice for flying personnel. In the same way, I hope that ATC's make the same sort of deal with themselves, regarding avoiding action scenarios.
Invictus
If I understand your questions properly, then;
When ATC's realize that the aircraft under their control have lost (or are about to lose) separation, the natural course is to take positive action, that is the overriding impulse. To provide "if ... then" instructions is not quite positive enough, because the result is one of two (unknown) possibilities. Sitting down after the fact and considering how it might or should have been handled is not even nearly the same as being there and then, and realizing that these guys are going to get way too close for comfort.
Regarding RA's being passed to the ATC system, IMHO, the problem with that is that the update of the Radar (in conventional systems) is too slow and thus will not be as accurate as the STCA, possibly providing outdated and inaccurate advice.
When this accident happened, there was a pilot that made a statement on these forums, he said that before he did any pre-start checks or anything else, he would say to the other pilot "We agree here and now that when we get an RA, we don't think, we just do it"
Honestly, I cannot think of any better advice for flying personnel. In the same way, I hope that ATC's make the same sort of deal with themselves, regarding avoiding action scenarios.
Invictus
Joined: Apr 2004
Posts: 34
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From: France
Am I the only one to think that if the exact same conditions were repeated, the accident would certainly not occur? The likeliness of a mid air collision at those speeds is just amazingly low; at 360m/s just 0.1s later there would have been no physical contact! maybe the turbulences would still have destroyed the plane behind, but nonetheless, their time had come.
When money is involved, it's always worth IMHO to evaluate how many lifes can be saved in what circumstances.. Correcting this situation with high cost installations is not worth it even if I was to be on a fatal path, me thinks. This money could save much more lifes applied to other issues.. 'tinfoil hat on'
When money is involved, it's always worth IMHO to evaluate how many lifes can be saved in what circumstances.. Correcting this situation with high cost installations is not worth it even if I was to be on a fatal path, me thinks. This money could save much more lifes applied to other issues.. 'tinfoil hat on'
Joined: Jan 2001
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From: UK
When this accident happened, there was a pilot that made a statement on these forums, he said that before he did any pre-start checks or anything else, he would say to the other pilot "We agree here and now that when we get an RA, we don't think, we just do it"
It is quite hard to back away from jumping to conclusions from this report, and proposing "solutions". The real solution was re-emphasised within weeks of the accident. Follow the RA every time... We can see that the "system" failed here, in that the TU-154M Flight Manual was confused over this issue. It is not surprising it was confused, in that the airline only carried TCAS outside the CIS area, and TCAS type procedures were not common to CIS based airlines. That lesson is now learnt.
I do not think it worth getting into discussions / technology for integrating TCAS and ATC. ATC is our prime collision avoidance measure. TCAS only steps in when ATC has (rarely) failed us. Why now involve the "failed system" anymore?
An analogy is a GPWS warning. We primarily avoid mountains by navigation and general awareness. When the GPWS warning goes off, if the pilot now still tries to bring his "situational awareness" into account, he usually fails, and dies. We need to now assume that the GPWS is correct, our navigation has failed, and follow the GPWS faithfully until the GPWS has shut up and we can only now try and restore the navigation awareness . Until that point, believe the "last ditch safety system" 100%!
The Mgmt type lessons of course, are overwhelming, and I trust being dealt with...
The Original Party Animal
Joined: Dec 2000
Posts: 375
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From: Around the corner
So far this thread has been very objective (partly thanks to the Mods...). Congrats to all who have contributed to it.
Re the SMOP (Single Manned OPeration), meaning only one ATCO working on position, be it a control sector during the day, or be it at night when all the sectors ar combined to one, it has to be remembered that this always has been and still is common practice in various ATCs worldwide, hence it is not only a Skyguide issue. This includes TWR, APP and ACC (Area Control).
I totally agree that this has to be addressed, and it has been dealt with at Skyguide, no more SMOP there.
It will be interesting to see if ICAO and/or EUROCONTROL and other local ATC bodies pick up the issue.
Re the SMOP (Single Manned OPeration), meaning only one ATCO working on position, be it a control sector during the day, or be it at night when all the sectors ar combined to one, it has to be remembered that this always has been and still is common practice in various ATCs worldwide, hence it is not only a Skyguide issue. This includes TWR, APP and ACC (Area Control).
I totally agree that this has to be addressed, and it has been dealt with at Skyguide, no more SMOP there.
It will be interesting to see if ICAO and/or EUROCONTROL and other local ATC bodies pick up the issue.
Joined: May 2004
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From: uk
So Spuds McKenzie maintains that Single Manned Operation is common practice in various ATC units worldwide...
Not in the civilised world old boy, where safety culture has been developed and refined through long and bitter experience. For an ATCO to leave an approach control position in order to deal with high level traffic is strictly forbidden. Not even the most basic ATC unit in darkest Africa would have behaved with such crass incompetence. From what we now know the ICAO position broadcast procedure on 126.90 could just as well have been applied to flights operating in the richest country in Europe!
The catalogue of errors made by Skyguide on that fateful evening defies belief and is now the subject of a criminal inquiry by the Swiss government.
My sympathy is with the Russian Captain. It was 2 to 1 against - the unfamiliar TCAS telling him to climb versus the Skyguide controller and his Chief Pilot (who was sitting next to him) ordering him forcefully to descend.
Not in the civilised world old boy, where safety culture has been developed and refined through long and bitter experience. For an ATCO to leave an approach control position in order to deal with high level traffic is strictly forbidden. Not even the most basic ATC unit in darkest Africa would have behaved with such crass incompetence. From what we now know the ICAO position broadcast procedure on 126.90 could just as well have been applied to flights operating in the richest country in Europe!
The catalogue of errors made by Skyguide on that fateful evening defies belief and is now the subject of a criminal inquiry by the Swiss government.
My sympathy is with the Russian Captain. It was 2 to 1 against - the unfamiliar TCAS telling him to climb versus the Skyguide controller and his Chief Pilot (who was sitting next to him) ordering him forcefully to descend.
The Original Party Animal
Joined: Dec 2000
Posts: 375
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From: Around the corner
die skyguide aka crashskyguide aka 694c
Still roaming about with different names, eh?
SMOP is still being exercised in Germany, Australia, NZ and others.
http://www.pprune.com/forums/showthr...hreadid=131193
SMOP is still being exercised in Germany, Australia, NZ and others.
Single Person nightshift staffing continues in Australia, including in Sydney and Brisbane.
Joined: Jul 2002
Posts: 115
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From: In the CIR
die skyguide......(nice pseudonym..NOT)
Go and read the story again and get your facts together. The co-jo wanted to follow the TCAS and was overuled!
SMOP indeed takes place in Germany on what they call the "quiet" sectors, with the blessing of the supervisor on duty!
Do all of the countries mentioned above not fit into your version of a civilised world?
My sympathy is with the Russian Captain
SMOP indeed takes place in Germany on what they call the "quiet" sectors, with the blessing of the supervisor on duty!
Do all of the countries mentioned above not fit into your version of a civilised world?
Not in the civilised world old boy
Joined: Feb 2001
Posts: 1,064
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From: Hants, UK
There is much concentration here on the role of ATC and confliction with TCAS etc.
What I have always found difficult to understand is why both or either crew continued with a course of action which plainly wasn't working. If you are established in a descent in reaction to a TCAS RA or an ATC command, and the relative level of the aircraft is not changing, why do you continue with it?
In broad figures, if a conflicting target indicates +00ft on your TCAS, you start to descend and it remains at or close to +00, then obviously another plan is needed, even of the instruments dictate otherwise. Even a 10 degree turn might have meant they missed each other.
In addition, the vis up there was greater than 10 km. Both aircraft had anti-collision lights and were aware of the other's presence. There was little or no other traffic about, and there was fairly good cloud cover preventing a myriad of ground lights from hiding the lights of the other aircraft. Even allowing for zero relative motion, why were the crews (and there were 4 of them on the 154) not able to look out of the window and see each other in those conditions? Was there (and is there still) perhaps too much reliance these days on the 'gizmos' to solve the problem and less on the basics of pilotage?
No disrespect intended to the deceased crews, but a basic question.
What I have always found difficult to understand is why both or either crew continued with a course of action which plainly wasn't working. If you are established in a descent in reaction to a TCAS RA or an ATC command, and the relative level of the aircraft is not changing, why do you continue with it?
In broad figures, if a conflicting target indicates +00ft on your TCAS, you start to descend and it remains at or close to +00, then obviously another plan is needed, even of the instruments dictate otherwise. Even a 10 degree turn might have meant they missed each other.
In addition, the vis up there was greater than 10 km. Both aircraft had anti-collision lights and were aware of the other's presence. There was little or no other traffic about, and there was fairly good cloud cover preventing a myriad of ground lights from hiding the lights of the other aircraft. Even allowing for zero relative motion, why were the crews (and there were 4 of them on the 154) not able to look out of the window and see each other in those conditions? Was there (and is there still) perhaps too much reliance these days on the 'gizmos' to solve the problem and less on the basics of pilotage?
No disrespect intended to the deceased crews, but a basic question.