Mid-Air Collision over Southern Germany (merged)
Well the media are reading what is posted here. This from the BBC...
http://news.bbc.co.uk/hi/english/wor...00/2082331.stm
Pilots have already hit back at the early Swiss move to blame the Russian crew.
"It seems incorrect to me for Swiss air traffic control to be already publicly blaming the Russian pilot 'because he did not respond to calls'," said one contributor to the Professional Pilots' Rumour Network website.
"Why did they not co-ordinate this action with the DHL aircraft?"
"Tragedies like this are caused by governments and authorities not addressing the problems we encounter every day," one writer added.
"It seems incorrect to me for Swiss air traffic control to be already publicly blaming the Russian pilot 'because he did not respond to calls'," said one contributor to the Professional Pilots' Rumour Network website.
"Why did they not co-ordinate this action with the DHL aircraft?"
"Tragedies like this are caused by governments and authorities not addressing the problems we encounter every day," one writer added.
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After seeing some posts re: altitude encoding problems from aircraft with metric altimetry systems, it would be good if someone really knowledgeable on this subject gave us his/her views!
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Condolences to all....very sad.
Some good posts, here, and sometimes (just sometimes) some idle speculation from aircrew brings up another investigation angle for the "experts". I heard that recently from a big wheel in the NTSB recently, at a conference dinner. They try, but can't always, think of all angles.....so PPRUNERS, don't necessarily be afraid to make informed speculations.
One other point here, to add to Capt Peacock's list:
For those of you who like to fly at night with the Cockpit lights on full bright in override because it's "less fatigueing", perhaps you might want to reconsider. Not saying it was a factor here, but lookout is as important as it ever was. ( Once had a relief crew fly me into the top of a rapidly building CB that they did not see, and had the radar tilted over the top of, resulting in a severe jolt and catering all over the place in the middle of the Pacific. I came out of the bunk to find sheepish faces in a full-bright flight deck - and lessons being learned)
Some good posts, here, and sometimes (just sometimes) some idle speculation from aircrew brings up another investigation angle for the "experts". I heard that recently from a big wheel in the NTSB recently, at a conference dinner. They try, but can't always, think of all angles.....so PPRUNERS, don't necessarily be afraid to make informed speculations.
One other point here, to add to Capt Peacock's list:
For those of you who like to fly at night with the Cockpit lights on full bright in override because it's "less fatigueing", perhaps you might want to reconsider. Not saying it was a factor here, but lookout is as important as it ever was. ( Once had a relief crew fly me into the top of a rapidly building CB that they did not see, and had the radar tilted over the top of, resulting in a severe jolt and catering all over the place in the middle of the Pacific. I came out of the bunk to find sheepish faces in a full-bright flight deck - and lessons being learned)
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Quite right CR, there is no single metric AFAIK which relates directly to the safety (or otherwise) of a particular type. But I do think the 154 gets a bad rep. for no particular reason other than it being a Tupolev. Undeserved IMO.
...the thin end thereof
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Nearly 24 hours after the accident, we are beginning to get an idea of how this terrible accident happened. As with almost all accidents involving professional aviation, it seems that this accident was multi-factorial in cause. I have my own theory on what happened and I hope I am not offending anyone by posting it here.
Swiss ATC (and it seems DHL) is blaming the Russian pilot, and Bashkirian Airlines are blaming Swiss ATC. I would imagine the truth is that the cause lay on both sides, and I think it's unfair for any side to 'blame' anyone because no-one wanted this to happen or indeed it seems was negligent to the point of being blameworthy.
Swiss ATC have admitted that the Tu-154 was given only 50 seconds to react to their initial call to descend. That in my opinion was the first cause of this accident. Error of Swiss ATC.
The pilot probably missed the first call. This is not uncommon especially in quiet airspace in the cruise at night when reactions are not at their most keen. To miss a second call is less common but does happen. However it seems this is what happened and that is likely cause number 2. Error of Bashkirian flight crew.
Thirdly, as has been suggested there was no instruction to the DHL 757 to take avoiding action when it became clear that the Tu-154 had not replied. Maybe the controller decided against this in preference to waiting for the expected reply from the Tu-154. Cause 3. Error of Swiss ATC.
By this time it is likely that both TCAS systems had given TA warnings and possibly RA warnings. If the TCAS operated correctly it would have instructed the Tu-154 to climb and the DHL 757 to descend. However crucially the Tu-154 had already been instructed to descend by ATC. Confusion, resulting in indecision followed by the decision to follow ATC's instruction. No human error - fault of the failure of the TCAS system to work as intended. Cause 4.
Cause 5. Bad luck. Even though both a/c were descending at the time of the collision, an accident was by no means inevitable as has been suggested on the TV news tonight. The chances of a collision were still small, especially since visibility was good. Instead of the catastrophe that happened, we would probably not find out about the incident for some time and it would be 'just another airprox incident'.
The only crew who were not at fault in any way were the DHL crew who were correctly following a TCAS RA to descend.
Swiss ATC (and it seems DHL) is blaming the Russian pilot, and Bashkirian Airlines are blaming Swiss ATC. I would imagine the truth is that the cause lay on both sides, and I think it's unfair for any side to 'blame' anyone because no-one wanted this to happen or indeed it seems was negligent to the point of being blameworthy.
Swiss ATC have admitted that the Tu-154 was given only 50 seconds to react to their initial call to descend. That in my opinion was the first cause of this accident. Error of Swiss ATC.
The pilot probably missed the first call. This is not uncommon especially in quiet airspace in the cruise at night when reactions are not at their most keen. To miss a second call is less common but does happen. However it seems this is what happened and that is likely cause number 2. Error of Bashkirian flight crew.
Thirdly, as has been suggested there was no instruction to the DHL 757 to take avoiding action when it became clear that the Tu-154 had not replied. Maybe the controller decided against this in preference to waiting for the expected reply from the Tu-154. Cause 3. Error of Swiss ATC.
By this time it is likely that both TCAS systems had given TA warnings and possibly RA warnings. If the TCAS operated correctly it would have instructed the Tu-154 to climb and the DHL 757 to descend. However crucially the Tu-154 had already been instructed to descend by ATC. Confusion, resulting in indecision followed by the decision to follow ATC's instruction. No human error - fault of the failure of the TCAS system to work as intended. Cause 4.
Cause 5. Bad luck. Even though both a/c were descending at the time of the collision, an accident was by no means inevitable as has been suggested on the TV news tonight. The chances of a collision were still small, especially since visibility was good. Instead of the catastrophe that happened, we would probably not find out about the incident for some time and it would be 'just another airprox incident'.
The only crew who were not at fault in any way were the DHL crew who were correctly following a TCAS RA to descend.
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The big sky theory just shrunk. With today’s technologically advanced navigation systems, aircraft can track laterally within meters of each other. Add in:
Condolences to all...
- a fixed point (intersection)
- Area ATC handover point
- Multiple language accents operating in a common language
- Expanded frequency digits (i.e. 123.245 MHz)
- A crew that was quite likely not familiar with that particular chunk of airspace
- Aircraft that were manufactured and equipped under different philosophical and regulatory requirements
Condolences to all...
Last edited by Orca strait; 2nd Jul 2002 at 21:53.
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The ATCOs involved are what I am thinking about,too. I won´t be able to sleep tonight...keep seeing coasted targets disappear and getting no answers anymore...
Hope that we will all (also management) learn from it...
Hope that we will all (also management) learn from it...
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Two years ago I posted on the limitations of TCAS or more importantly, our correct response to its request. I will include this story again whilst making no judgement on either of the two crews involved. It is an indication of the predicament within which we could all find ourselves.
22nd. July, 1999. Azores airspace near UTEM FL370. Early morning, after sunup.
Taking rest in LH seat with co-pilot flying. Map range unfortunately left in 160 mile range(don,t do this guys).
Awoken by co-pilot to be told that an aircraft, seen on tcas to have been cruising 1000ft. below,on closing heading, was now climbing to our level. Shortly after focusing my eyes we received the TA then "descend" RA. In my case my forward vision was blocked by visors placed to stop my co-pilot being blinded by the rising sun. on the strength of the TCAS alert I obeyed the collision avoidance command to descend, with a map range of 160 miles.
Unfortunately the other aircraft having realised that all was not correct seems to have also descended, probably initiating his descent a fraction of a second before his TCAS had told him to climb. So there we were, Boeing 767 & Airbus A340 both diving for the same bit of airspace!!!! So that is how easily it can happen.
We are advised to aquire the conflicting traffic visually at the intial TA alert but we wait for our TCAS to tell us what to do if no visual siting is possible. Now what happens if only one of the two aircraft sees the other. Does he wait for TCAS to sort things out,& if he reacts according to logic how can he be sure the timing will be correct & will not end up contradicting an RA recovery manoeuvre! In my case my No. 2 did see that the Airbus was not going to hit us but kept quite at that point to avoid any confusion.
Be aware of the limitations of the current TCAS system & its interface with you & me.
I repeat, no pre-judgement of either crew intended.
22nd. July, 1999. Azores airspace near UTEM FL370. Early morning, after sunup.
Taking rest in LH seat with co-pilot flying. Map range unfortunately left in 160 mile range(don,t do this guys).
Awoken by co-pilot to be told that an aircraft, seen on tcas to have been cruising 1000ft. below,on closing heading, was now climbing to our level. Shortly after focusing my eyes we received the TA then "descend" RA. In my case my forward vision was blocked by visors placed to stop my co-pilot being blinded by the rising sun. on the strength of the TCAS alert I obeyed the collision avoidance command to descend, with a map range of 160 miles.
Unfortunately the other aircraft having realised that all was not correct seems to have also descended, probably initiating his descent a fraction of a second before his TCAS had told him to climb. So there we were, Boeing 767 & Airbus A340 both diving for the same bit of airspace!!!! So that is how easily it can happen.
We are advised to aquire the conflicting traffic visually at the intial TA alert but we wait for our TCAS to tell us what to do if no visual siting is possible. Now what happens if only one of the two aircraft sees the other. Does he wait for TCAS to sort things out,& if he reacts according to logic how can he be sure the timing will be correct & will not end up contradicting an RA recovery manoeuvre! In my case my No. 2 did see that the Airbus was not going to hit us but kept quite at that point to avoid any confusion.
Be aware of the limitations of the current TCAS system & its interface with you & me.
I repeat, no pre-judgement of either crew intended.
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Very sad indeed
I have just watched the evening news (BBC & ITN and GRANADA as the DHL captain appears to be from Liverpool). Overall it appeared not a bad attempt from the BBC and ITN to put across what they thought they knew. Granada was worse telling how the DHL tried to 'dip' below the Russian jet.
The worst aspect for me has to be the DHL spokesperson who did himself and his company no favours by blatantly accusing the Russian crew of failing to respond to the ATC commands. He, like us, has no idea what was happening in that cockpit at the time. It would appear likely that the crew were attempting to deal with conflicting information (TCAS vs ATC) and may have had any other number of distractions at the same time. The FDR's will give a better idea and I am shocked that someone from within the industry will speak out so vehemently without having the full picture to hand. Decorum would have been a much better angle for him to pursue.
PP
I have just watched the evening news (BBC & ITN and GRANADA as the DHL captain appears to be from Liverpool). Overall it appeared not a bad attempt from the BBC and ITN to put across what they thought they knew. Granada was worse telling how the DHL tried to 'dip' below the Russian jet.
The worst aspect for me has to be the DHL spokesperson who did himself and his company no favours by blatantly accusing the Russian crew of failing to respond to the ATC commands. He, like us, has no idea what was happening in that cockpit at the time. It would appear likely that the crew were attempting to deal with conflicting information (TCAS vs ATC) and may have had any other number of distractions at the same time. The FDR's will give a better idea and I am shocked that someone from within the industry will speak out so vehemently without having the full picture to hand. Decorum would have been a much better angle for him to pursue.
PP
Some twenty years or so ago a unit I then worked at experienced a very close call in the middle of the night with only two aircraft on the sector. Low traffic unfortunately can sometimes lead to low levels of concentration/alertness. Then again it is not unusual, again in low traffic situations, for some controllers to leave a level change to two minutes prior, with a 2000 fpm rate - giving more than sufficient time when 1000 feet is all that's needed. In this particular case it appears (from official statements) that it was less than two minutes. Perhaps indeed the Tu-154 crew were just in the process of initiating the descent when their TCAS ordered "CLIMB". Possible hesitation........followed by the controllers repeated calls to descend may (speculation) have sadly misguided them into ignoring their TCAS. No doubt, as is so often the case with accidents, it will not come down to a single contributary cause. And no doubt when the final report emerges there will be lessons to be learned by both ATCOs and Aircrews alike.
Last edited by Avman; 2nd Jul 2002 at 22:22.
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RRamjet
I agree it is easier to see at night if you have the lights down, but this is no use if the dark FD environment puts the crew to sleep!
Please remember TCAS is an AID to collision avoidance, and only that, ATC is first line, TCAS helps second line (visual sighting), and itis only when these 2 fail that you should be relying solely on TCAS - then you have little other choice. Having said that, if you get a TCAS RA with non of the fisrt two options giving an input (ATC telling you where the traffic is, and/or you seeing it), you MUST respond, which appears to be what DHL did!
Just an additional note. With TCAS that I have flown, in addition to the call, you also have a display, so if either crew was not certain which way to go (ie. TU154 having descend from ATC and climb from TCAS) they SHOULD have been able to see from the display what the other A/C was doing vertically even if they could not see it visually.
RIP
I agree it is easier to see at night if you have the lights down, but this is no use if the dark FD environment puts the crew to sleep!
Please remember TCAS is an AID to collision avoidance, and only that, ATC is first line, TCAS helps second line (visual sighting), and itis only when these 2 fail that you should be relying solely on TCAS - then you have little other choice. Having said that, if you get a TCAS RA with non of the fisrt two options giving an input (ATC telling you where the traffic is, and/or you seeing it), you MUST respond, which appears to be what DHL did!
Just an additional note. With TCAS that I have flown, in addition to the call, you also have a display, so if either crew was not certain which way to go (ie. TU154 having descend from ATC and climb from TCAS) they SHOULD have been able to see from the display what the other A/C was doing vertically even if they could not see it visually.
RIP
Last edited by foxmoth; 2nd Jul 2002 at 22:35.
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Yaw String,
Why are you advised to try and get visual contact with the intruder?
It is not so that you can assess whether TCAS's RA is suitable or not.
You can not make that decision based on a visual spot - due to the difficulty in assessing relative altitude at high level (the horizon not being the same as the local horizontal).
The point of using a TA to get a visual spot is so that you can apply the normal rules of the air and Turn for collision avoidance.
TCAS is a good system, but not foolproof. Ultimately, if the other aircraft matchs your vertical manouevres, it will intersect with you vertically.
Fortunately, even if this happens, there is usually some lateral separation so instead of a collision an airprox results.
You want to miss the other guy. You can do that vertically or horizontally. Both would be nice, either is sufficient.
So, Fly the RA. This gives a very good chance of safety. Ignoring the RA is a 'Bad Idea' (tm).
But to cover the small possibility of system failure or the other aircraft manoeuvering opposite to its RA, supplement TCASs vertical RA with a Turn, either based on visual spotting or if offered by ATC.
So, to answer your scenario, if only one aircraft sees the other, a turn can save the day even if the RAs are compromised by incorrect pilot vertical response.
CPB
Why are you advised to try and get visual contact with the intruder?
It is not so that you can assess whether TCAS's RA is suitable or not.
You can not make that decision based on a visual spot - due to the difficulty in assessing relative altitude at high level (the horizon not being the same as the local horizontal).
The point of using a TA to get a visual spot is so that you can apply the normal rules of the air and Turn for collision avoidance.
TCAS is a good system, but not foolproof. Ultimately, if the other aircraft matchs your vertical manouevres, it will intersect with you vertically.
Fortunately, even if this happens, there is usually some lateral separation so instead of a collision an airprox results.
You want to miss the other guy. You can do that vertically or horizontally. Both would be nice, either is sufficient.
So, Fly the RA. This gives a very good chance of safety. Ignoring the RA is a 'Bad Idea' (tm).
But to cover the small possibility of system failure or the other aircraft manoeuvering opposite to its RA, supplement TCASs vertical RA with a Turn, either based on visual spotting or if offered by ATC.
So, to answer your scenario, if only one aircraft sees the other, a turn can save the day even if the RAs are compromised by incorrect pilot vertical response.
CPB
Please don't take this the wrong way but does the right hand rule of the air still apply?
IE. If head to head then break right, or the a/c that has the other on the right shall give way.
I remember this from my gliding days years ago, but does it apply to airliners?
I don't fly powered a/c so don't have a go and tell me that I should know this.
Obviously it is a moot point in this case but I thought I would ask.
IE. If head to head then break right, or the a/c that has the other on the right shall give way.
I remember this from my gliding days years ago, but does it apply to airliners?
I don't fly powered a/c so don't have a go and tell me that I should know this.
Obviously it is a moot point in this case but I thought I would ask.
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Swiss ATC knew B757 was diving when it instructed TU154 to descend
The following compiled from AP and SDA releases:
The Swiss air traffic controller on duty gave the crew of the Russian TU-154 aircraft only 50 seconds’ warning prior to the eventual mid-air collision. Earlier reports this morning (Tuesday) had referred to 1 ½ minutes.
Swiss ATC company Skyguide’s manager Urs Ryf confirmed that details released by German crash investigators about the timeline involved in the mid-air collision were correct. Accordingly, ATC instructions to reduce altitude were issued about 50 seconds prior to the collision. This morning (Tuesday) Skyguide had still maintained these had been issued up to two minutes earlier.
A second set of instructions was issued 25 seconds prior to the collision, as the Russian pilot had not reacted to the first advice. Ryf was not able to positively confirm whether a total of two or three sets of instructions had been issued by the controller to the Russian crew. “There were a couple of sets of instructions” he said. Skyguide, at this moment, is also adamant that the instructions were issued in a tight timeframe, but not too late. “All else has to be determined by the ongoing investigation” Ryf said.
A Swissair pilot with years of experience, Ruedi Bornhauser, said on a Swiss radio news broadcast that 50 seconds were by far sufficient notice to avoid a mid-air collision. In principle, he said, even 25 seconds would be time enough.
However, it is still unclear what type of collision avoidance system – if any - was fitted to the TU-154. Under normal circumstances, such a system would give its crew about 40 seconds’ warning. “And it would be only 25 seconds before the system would instruct to climb or dive” said Bornhauser.
It remains to be explained why ATC did not instruct the TU-154 crew to descend much earlier. Anton Maag, the Area Control Centre manager, commented that Swiss air space was very tight and that the work cadence of controllers on night duty was the same as during the day, despite there being fewer flights at night. This could be the reason why the controller on duty issued his instructions when he did. “He will have to comment on this point” says Jean Overney, Head of the Swiss air accident investigation bureau.
Skyguide also revealed that at the time of the mid-air collision at 23.35.40, the second controller on duty that night had been taking a break. At this point in time, there were another three planes within the Skyguide air space but 30 to 40 nm away from the collision site.
Skyguide were also in contact with the crew of the B-757, and had been so since that aircraft had entered Skyguide’s air space over the Swiss-Italian border. The pilot of the B-757 also informed ATC that he was following instructions of his TCAS to descend. This report from the Boeing crew was received immediately prior to the last set of instructions radioed to the TU-154 to descend, after which the collision happened.
The Swiss air traffic controller on duty gave the crew of the Russian TU-154 aircraft only 50 seconds’ warning prior to the eventual mid-air collision. Earlier reports this morning (Tuesday) had referred to 1 ½ minutes.
Swiss ATC company Skyguide’s manager Urs Ryf confirmed that details released by German crash investigators about the timeline involved in the mid-air collision were correct. Accordingly, ATC instructions to reduce altitude were issued about 50 seconds prior to the collision. This morning (Tuesday) Skyguide had still maintained these had been issued up to two minutes earlier.
A second set of instructions was issued 25 seconds prior to the collision, as the Russian pilot had not reacted to the first advice. Ryf was not able to positively confirm whether a total of two or three sets of instructions had been issued by the controller to the Russian crew. “There were a couple of sets of instructions” he said. Skyguide, at this moment, is also adamant that the instructions were issued in a tight timeframe, but not too late. “All else has to be determined by the ongoing investigation” Ryf said.
A Swissair pilot with years of experience, Ruedi Bornhauser, said on a Swiss radio news broadcast that 50 seconds were by far sufficient notice to avoid a mid-air collision. In principle, he said, even 25 seconds would be time enough.
However, it is still unclear what type of collision avoidance system – if any - was fitted to the TU-154. Under normal circumstances, such a system would give its crew about 40 seconds’ warning. “And it would be only 25 seconds before the system would instruct to climb or dive” said Bornhauser.
It remains to be explained why ATC did not instruct the TU-154 crew to descend much earlier. Anton Maag, the Area Control Centre manager, commented that Swiss air space was very tight and that the work cadence of controllers on night duty was the same as during the day, despite there being fewer flights at night. This could be the reason why the controller on duty issued his instructions when he did. “He will have to comment on this point” says Jean Overney, Head of the Swiss air accident investigation bureau.
Skyguide also revealed that at the time of the mid-air collision at 23.35.40, the second controller on duty that night had been taking a break. At this point in time, there were another three planes within the Skyguide air space but 30 to 40 nm away from the collision site.
Skyguide were also in contact with the crew of the B-757, and had been so since that aircraft had entered Skyguide’s air space over the Swiss-Italian border. The pilot of the B-757 also informed ATC that he was following instructions of his TCAS to descend. This report from the Boeing crew was received immediately prior to the last set of instructions radioed to the TU-154 to descend, after which the collision happened.
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In a collision situation it STILL makes sense to apply the RH rule, you then BOTH know which way you need to turn, and you BOTH turn out of each others way rather than one turning right and the other turning left
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There seems to be a lot of speculation as to why this happened, and the media are firmly pointing the finger of blame at the russian pilot. Did you read the Evening Standard? Judge jury and executioner springs to mind.
It appears to me that what has happened is similar to many other aviation incidents in that there was a combination of situations that coincided to create a fatal outcome. On its own, any of the circumstances may have passed without major problems, but it was the combination + bad timing multiplied by a great deal of bad luck.
I do hope this proves to be the case, however even if that happens, I doubt the media will be publishing appologies for pointing the finger of blame so prematurely in the future. They will get away with bloody rotten journalism - again.
It appears to me that what has happened is similar to many other aviation incidents in that there was a combination of situations that coincided to create a fatal outcome. On its own, any of the circumstances may have passed without major problems, but it was the combination + bad timing multiplied by a great deal of bad luck.
I do hope this proves to be the case, however even if that happens, I doubt the media will be publishing appologies for pointing the finger of blame so prematurely in the future. They will get away with bloody rotten journalism - again.