Mid-Air Collision over Southern Germany (merged)
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Seems as though notification of a TA downlinked thorough the mode S would have been especially useful here. While notice of the RA is helpful, it would just tell me (as a controller) that the mess had been taken out of my hands. On the other hand, notice of a TA would function as a "poor controller's" confilict alert...
I agree that an RA needs to be the priority to the aircrew. Even in a terminal environment, the TCAS has better resolution than my radar. But given that fact, and the fact that both aircrews were on the same frequency, I'd have liked to think that somebody would have mentioned something to the controller sometime between the TA and RA when no atc resolution appeared to be forthcoming. Don't misunderstand... this doesn't make it the aircrew(s)' fault. It's just that it seems to me that everybody EXCEPT the controller working this particular sector appeared to see this coming. At this point it appears that controllers in adjacent sectors tried to get involved, but I've heard nothing about one or both of the aircraft prompting the controller for a resolution after that point at which one would assume the TA would have been issued. That's not right. Neither crew would ever have flown through wx they thought too severe for the airframe, regardless of the atc vector provided. TAs need to be treated in exactly the same way. Get involved in the decision making process while it is young.
Again, this is not to implicate the aircrews. My point is simply to remind you folks in the pointy end of the airframe that you must not be shy when it seems as though the plan is going to hell. If you have information that makes your gut churn, share it with me. There is a line between those parts of the atc plan that are unclear and those parts of the atc plan that are simply a threat to your life. You've got a feel for it. If it appears to you that it's about to get really, really ugly, speak up. Please.
Dave
I agree that an RA needs to be the priority to the aircrew. Even in a terminal environment, the TCAS has better resolution than my radar. But given that fact, and the fact that both aircrews were on the same frequency, I'd have liked to think that somebody would have mentioned something to the controller sometime between the TA and RA when no atc resolution appeared to be forthcoming. Don't misunderstand... this doesn't make it the aircrew(s)' fault. It's just that it seems to me that everybody EXCEPT the controller working this particular sector appeared to see this coming. At this point it appears that controllers in adjacent sectors tried to get involved, but I've heard nothing about one or both of the aircraft prompting the controller for a resolution after that point at which one would assume the TA would have been issued. That's not right. Neither crew would ever have flown through wx they thought too severe for the airframe, regardless of the atc vector provided. TAs need to be treated in exactly the same way. Get involved in the decision making process while it is young.
Again, this is not to implicate the aircrews. My point is simply to remind you folks in the pointy end of the airframe that you must not be shy when it seems as though the plan is going to hell. If you have information that makes your gut churn, share it with me. There is a line between those parts of the atc plan that are unclear and those parts of the atc plan that are simply a threat to your life. You've got a feel for it. If it appears to you that it's about to get really, really ugly, speak up. Please.
Dave
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av8boy; Your point is well taken.
Pilot's; As a matter of interest, in a 90 degree closing situation at the same level (FL360), both aircraft doing 450 knots gs, how long before the impact would the TA have sounded ?
Finally; I wonder if the investigators will hear any Traffic Calls on any of the recordings that may not have been heard by the ATC (working two positions).
Pilot's; As a matter of interest, in a 90 degree closing situation at the same level (FL360), both aircraft doing 450 knots gs, how long before the impact would the TA have sounded ?
Finally; I wonder if the investigators will hear any Traffic Calls on any of the recordings that may not have been heard by the ATC (working two positions).
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We are going the wrong way with all "talk to ATC", "Inform ATC" with TAs / RAs.
In general, if you even get a TA, the ATC system has failed (they've scr*wed up, or you as a pilot have failed to follow an instruction, or done something not cleared).
The TA is (sometimes literally!) the "wake up call". It is now eyes out to try and detect him visually, and make a plan (maybe looking at the display) / prepare for the RA. It is only some 15s from TA to RA, and the RA must then be followed. Not time to try and get a word in to ATC, and try to explain the problem (as hinted earlier - that might be an idea well prior to the TA if you are studying the display), and await ATC's opinion. If there is any time for "discussion", it needs to be between the crew - CRM etc.
Blacksheep <<once an RA is issued, effective Air Traffic Control has already failed>> I'd say once the TA is issued, it has failed (except the frequent TAs on non-Mode C aircraft)
NoD
In general, if you even get a TA, the ATC system has failed (they've scr*wed up, or you as a pilot have failed to follow an instruction, or done something not cleared).
The TA is (sometimes literally!) the "wake up call". It is now eyes out to try and detect him visually, and make a plan (maybe looking at the display) / prepare for the RA. It is only some 15s from TA to RA, and the RA must then be followed. Not time to try and get a word in to ATC, and try to explain the problem (as hinted earlier - that might be an idea well prior to the TA if you are studying the display), and await ATC's opinion. If there is any time for "discussion", it needs to be between the crew - CRM etc.
Blacksheep <<once an RA is issued, effective Air Traffic Control has already failed>> I'd say once the TA is issued, it has failed (except the frequent TAs on non-Mode C aircraft)
NoD
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I work in a very busy TMA environment (which also happens to be short of staff), we often give small climbs/descents. I try and give you traffic info and reduce rate of climbs/descents and I often hear ''Traffic Traffic'' in the background on the radio.
Therefore I must disagree with NigelonDraft saying the ATC system has failed if he receives a TA.
How often do Pilots receive TA's,espeacially in the TMA's?
Therefore I must disagree with NigelonDraft saying the ATC system has failed if he receives a TA.
How often do Pilots receive TA's,espeacially in the TMA's?
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SD, According to my notes, and I'm sure CPB will correct me if I'm wrong, above FL200, with a sensitivity level of 7 (which would be the case) you would get a TA at 48 secs and an RA at 35 secs.
In cases where the rate of closure is very low the range boundaries are modified to allow TCAS to use a fixed-range threshold to issue TA's and RA's ie. again above FL200 you would get a TA at 1.3 nm or 850 ft and an RA at 1.1 nm or 600 ft.
Hope this helps shed some light.
In cases where the rate of closure is very low the range boundaries are modified to allow TCAS to use a fixed-range threshold to issue TA's and RA's ie. again above FL200 you would get a TA at 1.3 nm or 850 ft and an RA at 1.1 nm or 600 ft.
Hope this helps shed some light.
Pegase Driver
Setting the record straight on TCAS/Zurich/Russians and ATC
I wanted to stay out of this debate having seen so many posts in various forums that made me wonder who we were
..
Now, Danny, sorry to start a new thread on this but , I will now try to add a bit of information on the many posts spread over many forums : Rep points on the LSZH collision, on TCAS, but also on the Tech log ( TCAS coordination, Tcas, Tcas altitude, etc..) and on the ATC Forum ( collision above Germany )
Now this is going to be a bit long, but if you are a Journalist or a Pilot, or a Controller and want to understand TCAS and possibly what happennned last week in LSZH , bear with me for a few minutes :
First the History ( You can skip that intro if you are in a hurry )
TCAS is not the wondermachine that some claim it is. It has never been and probably never will.
Its hasty introduction by the FAA was motivated by political reasons, not safety ones. Congress pressed the FAA, and some lawyers argued that if we had a machine.available and another collision was to happen, the FAA could be held liable. That the CAS logic was not perfect did not play a role.
It was also recognised at the time that the logic could induce collisions that would normally not have happenned had TCAS not been there. The manufacturers call this , “TCAS limitations “the RCTA call these : Induced Collision risk “ We knew from the outset that TCAS , by its conception had the possibility to cause collisions. The percentage was identified. Nevertheless the risk was taken.
Studies were made showing those risks.. They rarely did made the ops rooms , or the cockpits .
TCAS was mandated in the USA with an imperfect logic and was tested in live traffic. When the fisrt scary crossing RAs occurred changes in the logic started to appear, 6.0. them 6.04, then 6.04 A …each trying to cure one or more potentially dangerous problems identified after its implementation .
.
The Europeans had to mandate TCAS also for legal reasons, they would have ben held legally responsible if a collision did occur that could have been saved should TCAS be mandated. But as Europe wanted to introduce RVSM and he US TCAS version mandated at the time (6.04.A) could not sustain RVSM operations, they created a version 7, wich is now renamed ACAS II (as TCAS is a brand name ). TCAS version 7.0 and ACAS II are the same thing.
TCAS version 7 h as delayed the reaction time to elminate most ( but not all ) the problems caused by RVSM. In fact the USA could not legally mandate version 7.0 at the time because it was a degradation in the protection from the previous version.
One could argue that the potential risks of TCAS induced colisions is greater with version 7.0 . ( but I do not have the numbers to prove it )
Now to the TCAS logic itself :
To function properly ACAS II ( i.e to prevent a collision ) some rules have to be followed :
Pilots should follow the first RA within 5 seconds and any subsequent corrective RA within 2,5 seconds.
Pilots should NEVER ever manoeuver in the opposite direction from an RA.
You can find this in the ACAS2 users manuals, the training manuals, but stangely enough not in the ICAO documents that set the regulation.
THE REGLEMENTATION :
What a controller should do is defined in ICAO PANS-RAC Doc 4444 : on the para defining responsibilities of controllers providing a service to ACAS equipped aircraft one can read :
Quote : “ Provision of [ ATC] shall be identical wether the aircraft is TCAS equipped or not. This means that the controller remains responsible for establishing and maintaining the relevant ATC separation as long as no RA is being followed bu the aircrew. When a pilot reports a manoeuvre due to an RA, the controller SHALL not attempt to modify the aircraft trajectory, but shall provide relevant traffic information (if possible.)
Based on the info I have, the controller in Zurich did exactly this. ( the conflict was detected very late, but that is another debate )
The use of ACAS by.Pilots is defined in ICAO PANS-OPS Doc 8168. And I quote it :
“nothing […] shall prevent pilots in command from exercision their best judgement and full authority in the choice of the best course of action to resolve a conflict.
The pilot shall use ACAS information in accordance with the following […]
The pilot SHALL not manoeuvre on the sole basis of a TA.
During an RA the pilot SHALL visually monitor the airspace where the intruder is indicated.
The deviation from ATC clearance shall be the minimum required.
[….]
Now this is not exactly what some of the training manuals say : you have to follow RA regardless of anything else, including ATC clearances if those areconflicting with RAs. ( or even the JAA guidelines ( TG 11 ) .
The main reason for this difference is the induced collision risk in the CAS logic. But ICAO is the only legal binding document that every pilot and controller should follow.
NOW to ZURICH :
From what I know so far the Zurich collision fell exactly into the induced risk in the CAS logic. My reasoning is : Should TCAS had not been present in that case would the collision had been prevented.
You have to answer yes, so here you are. TCAS caused this collision. Not pleasant to hear for some, but this is the ( legal ) reality.
Did the pilots follow ICAO guidelines (looking for each other , but in doing so delaying the follow of the RAs well beyond the 5 seconds required ) or did one ( or possibly both ) pilots manoeuvrered opposite to the RA, against the recommendations of the User manuals …
The lawyers are going to have a good day.
THE RUSSIANS :
What I hate to read is this constant bashing of the Russian pilots or equipment, implying they are inferior to us. My experience with russian pilots is that they are normally better trained that their western counterpart.
The Russian workhorse the TU154 is an excellent aircraft, suited to the area it operates. Yes it uses 3,8 times the fuel of an A320 to carry the same number of pax but it cost less than one tenth to buy. So who are we to deny some no so rich states to opearte it ?
Yes they are still building it, yes it can be made RVSM compliant, yes it can be fitted with ACAS.
The pilot(s) of that perticular flight spoke excelent english, (confirmed by previous controllers ) and the aircraft was equipped and RVSM monitored less than an hour before by the Linz HMU and found within RVSM tolerance.
Having an RA to climb and following an ATC clearance ( if that is proven to be the case, I ‘d like to hear the rest of the CVR to hear the subsequent RAs he got ) is possibly an error to some. But what would YOU have done ? the studies I have seen on (Western) piloys performance to follow RA is appalling : less that half follow the Ras as prescribed . In one airline ALL the pilots chooosed to ignore the Ras they had.. (training surely but nevertheless ..)
So my friend, a bit of respect for our Russian colleagues. Please …
FINALLY to my felow CONTROLLERS :
Those who posted , or declared that it could not happen “ here” are fooling themselves. What happened in LSZH could have happenned, and can still happen to ANY OF US. Those who beleive that they will never be alone one day on a sector, without STCA ( for those lucky to have one !) in a degraded system and will never spot a conflict late are really kidding themselves.
CONCLUSION : like in any story one myust conclude positively ;
I would like to give a few advices :
To my felow pilots : Whatever you decide to do , Do not EVER manoeuvre in the opposite direction of an RA.
To my fellow controllers, if you spot a conflict late nowadays with TCAS around, if you can , add a TURN to your climb/descent clearance.
To journalists : ask a few questions and do a minimum of investigation before writing.
The biggest shame I feel today, is that not to have been stronger 12 years ago when we had the chance to influence TCAS introduction. We thought those : TCAS induced collisions “ were numbers far away. Now I know one had a name : Zurich .
..
Now, Danny, sorry to start a new thread on this but , I will now try to add a bit of information on the many posts spread over many forums : Rep points on the LSZH collision, on TCAS, but also on the Tech log ( TCAS coordination, Tcas, Tcas altitude, etc..) and on the ATC Forum ( collision above Germany )
Now this is going to be a bit long, but if you are a Journalist or a Pilot, or a Controller and want to understand TCAS and possibly what happennned last week in LSZH , bear with me for a few minutes :
First the History ( You can skip that intro if you are in a hurry )
TCAS is not the wondermachine that some claim it is. It has never been and probably never will.
Its hasty introduction by the FAA was motivated by political reasons, not safety ones. Congress pressed the FAA, and some lawyers argued that if we had a machine.available and another collision was to happen, the FAA could be held liable. That the CAS logic was not perfect did not play a role.
It was also recognised at the time that the logic could induce collisions that would normally not have happenned had TCAS not been there. The manufacturers call this , “TCAS limitations “the RCTA call these : Induced Collision risk “ We knew from the outset that TCAS , by its conception had the possibility to cause collisions. The percentage was identified. Nevertheless the risk was taken.
Studies were made showing those risks.. They rarely did made the ops rooms , or the cockpits .
TCAS was mandated in the USA with an imperfect logic and was tested in live traffic. When the fisrt scary crossing RAs occurred changes in the logic started to appear, 6.0. them 6.04, then 6.04 A …each trying to cure one or more potentially dangerous problems identified after its implementation .
.
The Europeans had to mandate TCAS also for legal reasons, they would have ben held legally responsible if a collision did occur that could have been saved should TCAS be mandated. But as Europe wanted to introduce RVSM and he US TCAS version mandated at the time (6.04.A) could not sustain RVSM operations, they created a version 7, wich is now renamed ACAS II (as TCAS is a brand name ). TCAS version 7.0 and ACAS II are the same thing.
TCAS version 7 h as delayed the reaction time to elminate most ( but not all ) the problems caused by RVSM. In fact the USA could not legally mandate version 7.0 at the time because it was a degradation in the protection from the previous version.
One could argue that the potential risks of TCAS induced colisions is greater with version 7.0 . ( but I do not have the numbers to prove it )
Now to the TCAS logic itself :
To function properly ACAS II ( i.e to prevent a collision ) some rules have to be followed :
Pilots should follow the first RA within 5 seconds and any subsequent corrective RA within 2,5 seconds.
Pilots should NEVER ever manoeuver in the opposite direction from an RA.
You can find this in the ACAS2 users manuals, the training manuals, but stangely enough not in the ICAO documents that set the regulation.
THE REGLEMENTATION :
What a controller should do is defined in ICAO PANS-RAC Doc 4444 : on the para defining responsibilities of controllers providing a service to ACAS equipped aircraft one can read :
Quote : “ Provision of [ ATC] shall be identical wether the aircraft is TCAS equipped or not. This means that the controller remains responsible for establishing and maintaining the relevant ATC separation as long as no RA is being followed bu the aircrew. When a pilot reports a manoeuvre due to an RA, the controller SHALL not attempt to modify the aircraft trajectory, but shall provide relevant traffic information (if possible.)
Based on the info I have, the controller in Zurich did exactly this. ( the conflict was detected very late, but that is another debate )
The use of ACAS by.Pilots is defined in ICAO PANS-OPS Doc 8168. And I quote it :
“nothing […] shall prevent pilots in command from exercision their best judgement and full authority in the choice of the best course of action to resolve a conflict.
The pilot shall use ACAS information in accordance with the following […]
The pilot SHALL not manoeuvre on the sole basis of a TA.
During an RA the pilot SHALL visually monitor the airspace where the intruder is indicated.
The deviation from ATC clearance shall be the minimum required.
[….]
Now this is not exactly what some of the training manuals say : you have to follow RA regardless of anything else, including ATC clearances if those areconflicting with RAs. ( or even the JAA guidelines ( TG 11 ) .
The main reason for this difference is the induced collision risk in the CAS logic. But ICAO is the only legal binding document that every pilot and controller should follow.
NOW to ZURICH :
From what I know so far the Zurich collision fell exactly into the induced risk in the CAS logic. My reasoning is : Should TCAS had not been present in that case would the collision had been prevented.
You have to answer yes, so here you are. TCAS caused this collision. Not pleasant to hear for some, but this is the ( legal ) reality.
Did the pilots follow ICAO guidelines (looking for each other , but in doing so delaying the follow of the RAs well beyond the 5 seconds required ) or did one ( or possibly both ) pilots manoeuvrered opposite to the RA, against the recommendations of the User manuals …
The lawyers are going to have a good day.
THE RUSSIANS :
What I hate to read is this constant bashing of the Russian pilots or equipment, implying they are inferior to us. My experience with russian pilots is that they are normally better trained that their western counterpart.
The Russian workhorse the TU154 is an excellent aircraft, suited to the area it operates. Yes it uses 3,8 times the fuel of an A320 to carry the same number of pax but it cost less than one tenth to buy. So who are we to deny some no so rich states to opearte it ?
Yes they are still building it, yes it can be made RVSM compliant, yes it can be fitted with ACAS.
The pilot(s) of that perticular flight spoke excelent english, (confirmed by previous controllers ) and the aircraft was equipped and RVSM monitored less than an hour before by the Linz HMU and found within RVSM tolerance.
Having an RA to climb and following an ATC clearance ( if that is proven to be the case, I ‘d like to hear the rest of the CVR to hear the subsequent RAs he got ) is possibly an error to some. But what would YOU have done ? the studies I have seen on (Western) piloys performance to follow RA is appalling : less that half follow the Ras as prescribed . In one airline ALL the pilots chooosed to ignore the Ras they had.. (training surely but nevertheless ..)
So my friend, a bit of respect for our Russian colleagues. Please …
FINALLY to my felow CONTROLLERS :
Those who posted , or declared that it could not happen “ here” are fooling themselves. What happened in LSZH could have happenned, and can still happen to ANY OF US. Those who beleive that they will never be alone one day on a sector, without STCA ( for those lucky to have one !) in a degraded system and will never spot a conflict late are really kidding themselves.
CONCLUSION : like in any story one myust conclude positively ;
I would like to give a few advices :
To my felow pilots : Whatever you decide to do , Do not EVER manoeuvre in the opposite direction of an RA.
To my fellow controllers, if you spot a conflict late nowadays with TCAS around, if you can , add a TURN to your climb/descent clearance.
To journalists : ask a few questions and do a minimum of investigation before writing.
The biggest shame I feel today, is that not to have been stronger 12 years ago when we had the chance to influence TCAS introduction. We thought those : TCAS induced collisions “ were numbers far away. Now I know one had a name : Zurich .
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Nigel,
I was under the impression that ICAO didn't make laws. Therefore how can any document they produce be legally binding?
AFAIK contracting states to the Chicago Convention agree to take the ICAO rules/regulations/recommendations and incorporate them into their laws where applicable.
Another AFAIK. The ICAO recommendations are the minimum requirement to comply thus because ICAO didn't state that the pilots follow the RA above ATC doesn't mean that manuals/etc that say otherwise are wrong to do so.
I could be wrong. Wouldn't be the first time. Sure as hell wont be the last.
I was under the impression that ICAO didn't make laws. Therefore how can any document they produce be legally binding?
AFAIK contracting states to the Chicago Convention agree to take the ICAO rules/regulations/recommendations and incorporate them into their laws where applicable.
Another AFAIK. The ICAO recommendations are the minimum requirement to comply thus because ICAO didn't state that the pilots follow the RA above ATC doesn't mean that manuals/etc that say otherwise are wrong to do so.
I could be wrong. Wouldn't be the first time. Sure as hell wont be the last.
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Over & Out...
Re your <<Therefore I must disagree with NigelonDraft saying the ATC system has failed if he receives a TA>>
I may have been a bit misleading. I was referring to the TA where both aircraft have Mode C. By far and away the majority of TAs, and hopefully the ones you are hearing, are between a TCAS aircraft, and a squawking, but not Mode C, aircraft. TCAS therefore assumes the worst for the height of the other aircraft and issues a TA... but will not give an RA here. BIG is an example, where every puddle jumper in the circuit, with Mode A, but not C, sets off TAs in every aircraft in the BIG hold!
A TA is given ~45s before predicted point of closest proximity, and when that point is below some threshold. That is not a lot of time, and I cannot recall a TA between 2 Mode C aircraft I have had where someone was not cutting things a bit tight - either ATC, or one or both aircraft employing non-sensible RoC / RoD.
Furthermore, I did try the clarify the words "ATC System" has failed. That is more than the ATCO, and his equipment. The "system" to me also includes pilots then following ATC instructions and clearances...
I could, of course be mistaken, and a particularly tight ATC vectoring environment might lead to frequent TAs. If so, maybe the system is trying to say that things are a bit tight!
NoD
Re your <<Therefore I must disagree with NigelonDraft saying the ATC system has failed if he receives a TA>>
I may have been a bit misleading. I was referring to the TA where both aircraft have Mode C. By far and away the majority of TAs, and hopefully the ones you are hearing, are between a TCAS aircraft, and a squawking, but not Mode C, aircraft. TCAS therefore assumes the worst for the height of the other aircraft and issues a TA... but will not give an RA here. BIG is an example, where every puddle jumper in the circuit, with Mode A, but not C, sets off TAs in every aircraft in the BIG hold!
A TA is given ~45s before predicted point of closest proximity, and when that point is below some threshold. That is not a lot of time, and I cannot recall a TA between 2 Mode C aircraft I have had where someone was not cutting things a bit tight - either ATC, or one or both aircraft employing non-sensible RoC / RoD.
Furthermore, I did try the clarify the words "ATC System" has failed. That is more than the ATCO, and his equipment. The "system" to me also includes pilots then following ATC instructions and clearances...
I could, of course be mistaken, and a particularly tight ATC vectoring environment might lead to frequent TAs. If so, maybe the system is trying to say that things are a bit tight!
NoD
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Nigel,
TCAS is far from perfect and TAs and RAs can occur in a perfectly safe environment.
To prove my point I've got first hand experience:
SQ 747 climbing to FL150, ROC ~2500ft/min. (to get above terrain).
SR MD11 on opposite track descending FL160, ROD ~2500ft/min.
MD11 passing FL167, saying "TCAS climb" and pulling up to FL170 again; 747 saying "TCAS alert", but no action.
Conclusion:
Since both acft had a relatively high ROC/ROD, TCAS's calculated MD11 descending through 160 and 747 climbing through 150.
Note: No ATC sc*ew up, no pilot's sc*ew up.
TCAS is far from perfect and TAs and RAs can occur in a perfectly safe environment.
To prove my point I've got first hand experience:
SQ 747 climbing to FL150, ROC ~2500ft/min. (to get above terrain).
SR MD11 on opposite track descending FL160, ROD ~2500ft/min.
MD11 passing FL167, saying "TCAS climb" and pulling up to FL170 again; 747 saying "TCAS alert", but no action.
Conclusion:
Since both acft had a relatively high ROC/ROD, TCAS's calculated MD11 descending through 160 and 747 climbing through 150.
Note: No ATC sc*ew up, no pilot's sc*ew up.
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Flight standards
To ATC Watcher :
First thanks for clear and objective info.
Here is just remarks based on russian flight rules:
CREW OF CRASHED TU-154 AIRCRAFT HAD TO FULFIL INSTRUCTIONS OF AIR TRAFFIC CONTROLLER ONLY
MOSCOW, JULY 10 /RIA Novosti's Aleksei Berezin/ - Yuri Tashin, chief of the flight standards department, stated in Moscow at a press conference that the crew of the crashed TU-154 aircraft had had to fulfil only instructions of the air traffic controller without taking into account air collision avoidance equipment recommendations.
According to him, air space over Germany and Switzerland is considered to be the category "A" air space which means that airplanes in this area operate in the regime of permanent radio communications, and in any situation air traffic controllers' instructions are a priority.
First thanks for clear and objective info.
Here is just remarks based on russian flight rules:
CREW OF CRASHED TU-154 AIRCRAFT HAD TO FULFIL INSTRUCTIONS OF AIR TRAFFIC CONTROLLER ONLY
MOSCOW, JULY 10 /RIA Novosti's Aleksei Berezin/ - Yuri Tashin, chief of the flight standards department, stated in Moscow at a press conference that the crew of the crashed TU-154 aircraft had had to fulfil only instructions of the air traffic controller without taking into account air collision avoidance equipment recommendations.
According to him, air space over Germany and Switzerland is considered to be the category "A" air space which means that airplanes in this area operate in the regime of permanent radio communications, and in any situation air traffic controllers' instructions are a priority.
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Could you clarify your post PaC? Are you saying that the Swissair received an RA and the SQ received only a TA (which isn't really the way TCAS works), or that the SQ received an RA which did not require it to reverse direction, such as 'Adjust vertical speed'?. In the latter scenario TCAS worked as it should, interpreting a high closing rate as a threat to the aircrafts safety. TCAS has no knowledge of cleared levels, nor in my opinion should it as it would then not protect you against a loss of seperation caused by a level bust. By now everybody should know the risks of high rates of climb or descent near to their cleared level and adjust their flying to reflect that. The occasional false alarm is well worth the hassle compared to the number of saves it has made, even more so now that we have seen human error is a major factor in the mid-air.
As to the statements made by Yuri Tashin, perhaps if his airline wish to fly in European airspace in the future they should learn to operate to the same rules as most other aircraft. ACAS wouldn't be mandatory in RVSM airspace if you weren't meant to follow its instructions.
As to the statements made by Yuri Tashin, perhaps if his airline wish to fly in European airspace in the future they should learn to operate to the same rules as most other aircraft. ACAS wouldn't be mandatory in RVSM airspace if you weren't meant to follow its instructions.
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Proceed As Cleared
<<SR MD11 on opposite track descending FL160, ROD ~2500ft/min.
MD11 passing FL167, saying "TCAS climb" and pulling up to FL170 again; 747 saying "TCAS alert", but no action. >>
2 comments - firstly strange the 747 only got TA - should be co-ordinated RAs?
Second - you say <<no pilot's sc*ew up>> - I disagree, in TCAS terms. You are stating that the MD11 was still descending at 2500fpm with 700' to level off, AND (presumably) having received a TA on the 747, and STILL he descends at 2500fpm...?
TCAS does not have ESP. 2 aircraft, climbing / descending towards each other @5000fpm are some 1500' feet apart (I'm guessing at the 747 alt). This is about the 25s TCA works to before a collision... so seems to be working well to me.
2 points:
1. Again - if everyone follows the RAs they get, there will be no collision - might be untidy I agree.
2. As CPB said (another thread in ATC issues?) - TA = Reduce your VS !!! I think he said something like >1500fpm with less than 2000' to go = asking for an RA. Its not just avoiding TCAS RAs - smoother for the SLF as well.
I'm not saying we should all know this already - buts learn the lessons from this and other incidents.
NoD
<<SR MD11 on opposite track descending FL160, ROD ~2500ft/min.
MD11 passing FL167, saying "TCAS climb" and pulling up to FL170 again; 747 saying "TCAS alert", but no action. >>
2 comments - firstly strange the 747 only got TA - should be co-ordinated RAs?
Second - you say <<no pilot's sc*ew up>> - I disagree, in TCAS terms. You are stating that the MD11 was still descending at 2500fpm with 700' to level off, AND (presumably) having received a TA on the 747, and STILL he descends at 2500fpm...?
TCAS does not have ESP. 2 aircraft, climbing / descending towards each other @5000fpm are some 1500' feet apart (I'm guessing at the 747 alt). This is about the 25s TCA works to before a collision... so seems to be working well to me.
2 points:
1. Again - if everyone follows the RAs they get, there will be no collision - might be untidy I agree.
2. As CPB said (another thread in ATC issues?) - TA = Reduce your VS !!! I think he said something like >1500fpm with less than 2000' to go = asking for an RA. Its not just avoiding TCAS RAs - smoother for the SLF as well.
I'm not saying we should all know this already - buts learn the lessons from this and other incidents.
NoD
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Nigel,
Reading between the lines you suggest that I've made this up.
Nope, had both acft on my freq (and believe me, I nearly jumped off my seat, when I watched the MD11 pulling up and going about 2NM off track at the same time!).
Besides, this happened about 3 years ago, so don't quote me on what the pilots exactly said.
My point was, as I've stated, that this happened, although both acft were cleared safely and it was a bloody nuisance to me as an ATCO (adrenalin level jumped up a bit).
Reading between the lines you suggest that I've made this up.
Nope, had both acft on my freq (and believe me, I nearly jumped off my seat, when I watched the MD11 pulling up and going about 2NM off track at the same time!).
Besides, this happened about 3 years ago, so don't quote me on what the pilots exactly said.
My point was, as I've stated, that this happened, although both acft were cleared safely and it was a bloody nuisance to me as an ATCO (adrenalin level jumped up a bit).
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Bit concerned with Ruslans assertion that Russian pilots are not trained in RVSM / TCAS procedures! so what are they doing there then? Claiming that Swiss airspace is class A and therefore one can 'switch off' won't wash. It would appear that this could have been a unfortunate error resulting in an airmiss not a mid air. It would also seem that a significant portion of blame must rest with the Russian crew and their operating authorities. It won't do to simply hang the controller, the TCAS is there to prevent disasters, what's the point if you don't follow it? And don't lets cloud the issue with examples of TCAS failure or confusion, if it says Climb, the crews response should be automatic.
Of course, without TCAS (on both a/c) the Tu-154 would have passed 600 feet below. But had the controller forgotten them completely - and still no TCAS - they would have collided at FL360.
The controller and TCAS both contributed to this accident but they were not the cause. All now seems to point at the real cause being CONFLICTING COMPANY PROCEDURES .
The controller and TCAS both contributed to this accident but they were not the cause. All now seems to point at the real cause being CONFLICTING COMPANY PROCEDURES .
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Proceed As Cleared
<<Reading between the lines you suggest that I've made this up>>
Nothing could be further from the truth - what you say adds up to me completely.
My points are that TCAS has been introduced. It works as a useful backstop to ATC, and does not rely on external inputs i.e. "expected level off altitudes" etc. It purely looks at what aircraft are doing right now, and if they carry on in this way, will they get VERY close (I have had a German ATC screw up, and we in a 767 passed <1.5NM and ~400' above a piston twin - the RA was "Monitor VS" or similar i.e. it was happy with a 400' separation or so). In general I am very happy with it, and am sure it has saved lives.
However, in order to give TCAS a chance to work well, we all (pilots and ATC) must have the knowledge of how it works. In the case you quote, it would appear the pilots gave it little choice. As I said elsewhere, in the US they now have a rule that with less than 1000' to go RoD / RoC must be ~500fpm. In the case you quote, it would appear that this (sensible) rule would have prevented the RAs and ensuing hassle for all.
We have 2 choices:
1. Bin TCAS altogether
2. ALL pilots must ALWAYS follow RAs exactly - this may cause some hassle, but will avoid mid-airs.
A halfway house of some obeying them, some ignoring them, some querying them does not let TCAS work, and has had tragic consequences, and other near consequences, this week alone. Let us learn from these...
NoD
<<Reading between the lines you suggest that I've made this up>>
Nothing could be further from the truth - what you say adds up to me completely.
My points are that TCAS has been introduced. It works as a useful backstop to ATC, and does not rely on external inputs i.e. "expected level off altitudes" etc. It purely looks at what aircraft are doing right now, and if they carry on in this way, will they get VERY close (I have had a German ATC screw up, and we in a 767 passed <1.5NM and ~400' above a piston twin - the RA was "Monitor VS" or similar i.e. it was happy with a 400' separation or so). In general I am very happy with it, and am sure it has saved lives.
However, in order to give TCAS a chance to work well, we all (pilots and ATC) must have the knowledge of how it works. In the case you quote, it would appear the pilots gave it little choice. As I said elsewhere, in the US they now have a rule that with less than 1000' to go RoD / RoC must be ~500fpm. In the case you quote, it would appear that this (sensible) rule would have prevented the RAs and ensuing hassle for all.
We have 2 choices:
1. Bin TCAS altogether
2. ALL pilots must ALWAYS follow RAs exactly - this may cause some hassle, but will avoid mid-airs.
A halfway house of some obeying them, some ignoring them, some querying them does not let TCAS work, and has had tragic consequences, and other near consequences, this week alone. Let us learn from these...
NoD
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TCAS vs CONTROLLER
Having flown both within Russia as well as with pilots from the former soviet union, I do understand (not that I accept it) the hesitation and the decision to follow the order from a third party (the controller) against the TCAS RA.
I mean... In the eastern backlands the pilots have to make up excuses to request for a change of flight level (as you don't wanna upset the controller).
So - like in this case - you really don't start discussing resolution matters if a controller tells you to descend.
He's the CONTROLLER OF THE FLIGHT - and you might get rapped if he writes a report on you..
It's a conflict of cultures that occures. And - unfortunately - a conflict of aircraft this time.
-gothammer-
I mean... In the eastern backlands the pilots have to make up excuses to request for a change of flight level (as you don't wanna upset the controller).
So - like in this case - you really don't start discussing resolution matters if a controller tells you to descend.
He's the CONTROLLER OF THE FLIGHT - and you might get rapped if he writes a report on you..
It's a conflict of cultures that occures. And - unfortunately - a conflict of aircraft this time.
-gothammer-
Keeping Danny in Sandwiches
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I wonder if the answer is to put TCAS on a more formal basis.
Most RA’s are preceded by a TA. If when an aircraft receives a TA he immediately informs ATC with the phrase "Xyz123 Traffic Alert following TCAS" and disconnects the A/P he would not only prepare himself for what might, or might not happen, but also provide a positive indication to ATC that he is no longer in control. On 99% of occasions there will have been no reduction in separation and the action would have been unnecessary, however on that 1% it would bring everyone into the loop. The response by the other aircraft with the TA would then clearly identify the 2 aircraft.
On another point is it beyond the ability of the ATC software programmers to write the same criteria into their system so that not only does it have Conflict Alert but would also be able to predict the TCAS response a few seconds ealier?
The American policy of reducing R of C and D to 500fpm in the last 1,000ft should be adopted as SOP.
Most RA’s are preceded by a TA. If when an aircraft receives a TA he immediately informs ATC with the phrase "Xyz123 Traffic Alert following TCAS" and disconnects the A/P he would not only prepare himself for what might, or might not happen, but also provide a positive indication to ATC that he is no longer in control. On 99% of occasions there will have been no reduction in separation and the action would have been unnecessary, however on that 1% it would bring everyone into the loop. The response by the other aircraft with the TA would then clearly identify the 2 aircraft.
On another point is it beyond the ability of the ATC software programmers to write the same criteria into their system so that not only does it have Conflict Alert but would also be able to predict the TCAS response a few seconds ealier?
The American policy of reducing R of C and D to 500fpm in the last 1,000ft should be adopted as SOP.
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don't know about disconnecting the autopilot, but the rest sounds plausible...at the end of the day, the tcas system could be amended, so that when an RA is activated, atc becomes aware the aircraft is under "TCAS" control", and doesn't issue conflicting instructions...
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Feeding TCAS etc into the ATC system is not necessary, it may after all be 'down' for servicing. TCAS is a failsafe system, nothing more, it must be observed to work. If the Russians can't get their act in gear then they should be banned fron RVSM airspace until they can operate to western standards. They are obviously desperate to blaim the Swiss controller, bit unfair maybe.