Mid-Air Collision over Southern Germany (merged)
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Rotorbike:
It appears that the discrepancy in the number of children/adults is based on the type of tickets they held. Eight of the pax were on children's tickets (i.e. under 12 years of age), the others above that age seem to have been officially counted as adults.
Either way: a tragedy.
It appears that the discrepancy in the number of children/adults is based on the type of tickets they held. Eight of the pax were on children's tickets (i.e. under 12 years of age), the others above that age seem to have been officially counted as adults.
Either way: a tragedy.
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OneWorld22
Thank you, as you can imagine the office is not the usual warm and funny place. Lots of depressed people; this is the first major accident for DHL.
Thoughts go to our collegues who lost their lives, on both aircraft, but most of all to the innocent passengers in the Tupolev, and all of their families. I've probably met the B757 crew but don't recall their names.
May I kindly ask everybody to hold their theories back for a while, and act like professionals and wait for the official investigation. Please try not to do what the press does and jump to conclusions before knowing all the facts.
Thank you, as you can imagine the office is not the usual warm and funny place. Lots of depressed people; this is the first major accident for DHL.
Thoughts go to our collegues who lost their lives, on both aircraft, but most of all to the innocent passengers in the Tupolev, and all of their families. I've probably met the B757 crew but don't recall their names.
May I kindly ask everybody to hold their theories back for a while, and act like professionals and wait for the official investigation. Please try not to do what the press does and jump to conclusions before knowing all the facts.
Sims Fly Virtually
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Sad, sad, sad, Whatever the cause(s), rotten luck with a couple of aircraft a few hundred feet wide and all those millions of cubic feet of sky 
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Statement by Swiss ATC
Swiss ATC (Skyguide) have issued a preliminary statement. Their spokesman, Tony Maag, is reported as saying during a special broadcast by Swiss TV station SF DRS that Zurich ATC had been handed over both flights at 2330 local time. Five or six minutes later the crash happened. One of the two planes had not immediately followed instructions to descend to a lower altitude, and the controller was required to repeat his instructions twice or three times. During this process, the other plane’s TCAS had been activated and its crew had initiated a descent. This movement could no longer be controlled by Zurich ATC. The controller on duty is under shock, according to Maag. A comprehensive investigation has been announced.
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German authorities have announced that the flight data recorder of the TU-154 has been found.
They also have gone further in their official accounts of the events leading up to the mid-air collision.
Ulrich Müller, the Baden-Württemberg Transport Minister, has confirmed that the unsuccessful attempts by Swiss ATC (who are responsible for this sector despite its being over German territory) to direct one of the a/c to a lower FL were, in fact, addressed to the crew of the TU-154.
They also have gone further in their official accounts of the events leading up to the mid-air collision.
Ulrich Müller, the Baden-Württemberg Transport Minister, has confirmed that the unsuccessful attempts by Swiss ATC (who are responsible for this sector despite its being over German territory) to direct one of the a/c to a lower FL were, in fact, addressed to the crew of the TU-154.
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For the benfit of us who do not go above 10000 ft - At what stage does TCAS activate and alarm? How much time do you have to assess and react, especially on a nose to nose conflict in fast jetliners?
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Reports that the Russian party of children missed a connection in Moscow, and this aircraft was laid on for them at short notice. What a cruel twist of fate. Heard the BBC reporter mentioning that he was amazed that none of the wreckage killed anyone, as the wreckage fell on either side of Urlinghan town.
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TCAS Parameters
Flying Bean,
TCAS alerting is based on prediction of a 'Closest Point Of Approach' (or CPA).
If the predicted CPA is too small (horizontal and vertical values depend on Altitude - the higher you are the bigger the predicted 'miss' must be for TCAS to consider it safe) then a Resolution Advisory (RA) will be generated once the aircraft are within the RA Alerting Time.
This value also varies with altitude, from (if I recall correctly - manual not to hand) some 15 seconds at low levels to 35 seconds at high level.
The RA is preceded by a Traffic Advisory, 10 - 15 seconds earlier, depending on altitude.
Since it is a time parameter, the particular point you've raised, about a 'nose to nose conflict in fast jetliners' is not an issue.
i.e. the greater the rate of closure, the greater the distance at which the alerts are generated.
However, the increased time allocated to Alerts at high level does not translate into more time for 'assessment and reaction'. The reason more time is given is because:
a) Altimeter inaccuracies mean that a bigger vertical miss must be provided by TCAS to be sure of safety. I.E. aircraft could be at the same level even though in reported altitude terms they lcould look like they are a couple of hundred feet apart. Hence the safe separation required is effectively:
Worst Case scenario of altimeter innacuracy, X 2, + required actual separation.
b) High altitude make the aircraft less manoueverable (IAS / TAS relationship).
The alerting times are selected so that the aircraft has enough time to go from predicted co-altitude with intruder to safe separation, plus 5 seconds of reaction time for the crew.
As a final point, there are various eventualities that can delay or even prevent the TCAS response. However to go into them here would be verging on speculation.
If you require more information on TCAS function, I suggest a search on Tech Log.
CPB
(former) TCAS instructor.
TCAS alerting is based on prediction of a 'Closest Point Of Approach' (or CPA).
If the predicted CPA is too small (horizontal and vertical values depend on Altitude - the higher you are the bigger the predicted 'miss' must be for TCAS to consider it safe) then a Resolution Advisory (RA) will be generated once the aircraft are within the RA Alerting Time.
This value also varies with altitude, from (if I recall correctly - manual not to hand) some 15 seconds at low levels to 35 seconds at high level.
The RA is preceded by a Traffic Advisory, 10 - 15 seconds earlier, depending on altitude.
Since it is a time parameter, the particular point you've raised, about a 'nose to nose conflict in fast jetliners' is not an issue.
i.e. the greater the rate of closure, the greater the distance at which the alerts are generated.
However, the increased time allocated to Alerts at high level does not translate into more time for 'assessment and reaction'. The reason more time is given is because:
a) Altimeter inaccuracies mean that a bigger vertical miss must be provided by TCAS to be sure of safety. I.E. aircraft could be at the same level even though in reported altitude terms they lcould look like they are a couple of hundred feet apart. Hence the safe separation required is effectively:
Worst Case scenario of altimeter innacuracy, X 2, + required actual separation.
b) High altitude make the aircraft less manoueverable (IAS / TAS relationship).
The alerting times are selected so that the aircraft has enough time to go from predicted co-altitude with intruder to safe separation, plus 5 seconds of reaction time for the crew.
As a final point, there are various eventualities that can delay or even prevent the TCAS response. However to go into them here would be verging on speculation.
If you require more information on TCAS function, I suggest a search on Tech Log.
CPB
(former) TCAS instructor.
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Typically, there are two kinds of TCAS advisories, TA - Traffic Advisory and RA - Resolution Advisory.
Traffic advisory TA, is activated when another aircraft is about to intrude the TA protective envelope within approximately 40 sec. The envelope is 0.75 nm radius and 850 ft above and below your a/c. The TA will provide both visual and aural cues, ie the display will turn the color of the traffic from white to amber with the aural warning, i.e "Traffic, Traffic"
The Resolution advisory RA, is activated when another a/c is about to intrude the RA protective area within approximately 20 sec. The RA protective envelope is 0.30 nm and 600 ft above and below your a/c. The color of the symbol will now turn red and the aural warning and the maneuvering command will be displayed on the VSI with the aural warning, i.e "Climb, Climb Now!" "Climb, Climb Now!" Compliance with the commanded maneuver is required with 5 sec (2.5 for enhanced RA) of the aural warning with at least +/- 0.25 G maneuver.
"Clear of Conflict" will be announced once the traffic is well cleared.
There is a new version of TCAS called TCAS VII that is not widely used or required but it provides both vertical and lateral RA.
Note: TCAS will not be able to detect a/c that do not have operating transponder. They will not provide RA against non-altitude reporting transponder. It has automatic function to make coordination with the other TCAS equipped a/c in case of RA so both a/c's will not move in the same direction.
What I described above is how a TCAS II would operate and I believed that the B-757 is probably is equipped with such a system. No idea what was on the Tupolev, if any...
Condolences to all that perished.
Traffic advisory TA, is activated when another aircraft is about to intrude the TA protective envelope within approximately 40 sec. The envelope is 0.75 nm radius and 850 ft above and below your a/c. The TA will provide both visual and aural cues, ie the display will turn the color of the traffic from white to amber with the aural warning, i.e "Traffic, Traffic"
The Resolution advisory RA, is activated when another a/c is about to intrude the RA protective area within approximately 20 sec. The RA protective envelope is 0.30 nm and 600 ft above and below your a/c. The color of the symbol will now turn red and the aural warning and the maneuvering command will be displayed on the VSI with the aural warning, i.e "Climb, Climb Now!" "Climb, Climb Now!" Compliance with the commanded maneuver is required with 5 sec (2.5 for enhanced RA) of the aural warning with at least +/- 0.25 G maneuver.
"Clear of Conflict" will be announced once the traffic is well cleared.
There is a new version of TCAS called TCAS VII that is not widely used or required but it provides both vertical and lateral RA.
Note: TCAS will not be able to detect a/c that do not have operating transponder. They will not provide RA against non-altitude reporting transponder. It has automatic function to make coordination with the other TCAS equipped a/c in case of RA so both a/c's will not move in the same direction.
What I described above is how a TCAS II would operate and I believed that the B-757 is probably is equipped with such a system. No idea what was on the Tupolev, if any...
Condolences to all that perished.
Actually, it was A9C-DHL, c/n 24635 - on flight DHX611.
All DHL flights are regular customers in our airspace and we extend our sincere condolences to the staff and families of EAT/DHL, not forgetting of course the tragic loss of young lives on the Tu-154.
All DHL flights are regular customers in our airspace and we extend our sincere condolences to the staff and families of EAT/DHL, not forgetting of course the tragic loss of young lives on the Tu-154.
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some recent pics of the DHL aircraft on the ramp at BAH
they're a bit dark (tinted windows) and there's some nasty camera reflection
http://www.dhl.com.bh/images/bah/115-1575_IMG.JPG
http://www.dhl.com.bh/images/bah/115-1576_IMG.JPG
http://www.dhl.com.bh/images/bah/102-0235_IMG.JPG
they're a bit dark (tinted windows) and there's some nasty camera reflection
http://www.dhl.com.bh/images/bah/115-1575_IMG.JPG
http://www.dhl.com.bh/images/bah/115-1576_IMG.JPG
http://www.dhl.com.bh/images/bah/102-0235_IMG.JPG
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Devastating .... condolences to all involved.
Is the aircraft anything to do with EAT? Isn't there a Bahrain based DHL franchise?
Here are pictures of both aircraft involved:
http://www.airliners.net/open.file/062723/M/
http://www.airliners.net/open.file/183748/M/
ES
Is the aircraft anything to do with EAT? Isn't there a Bahrain based DHL franchise?
Here are pictures of both aircraft involved:
http://www.airliners.net/open.file/062723/M/
http://www.airliners.net/open.file/183748/M/
ES
Last edited by Electric Sky; 2nd Jul 2002 at 08:42.
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From what I can gather from these posts the DHL pilot was responding correctly to TCAS RA to fly down. Now if the TU154 was in RVSM I shouldn't it have TCAS installed as a requirement?; so shouldn't the two TCAS computers co-ordinate the avoidance action?
In any case, it is an accident which should have us all reflect that even in one of the best controlled airspaces with all the modern airborne equipment etc. we still need to be scanning that sky or at least scanning the ND continously for suspect TCAS targets in order to have as early a warning as possible of potential threats.
Another thing which I hope will *not* happen after this accident is that pilots will become wary of following TCAS RAs if it transpires that the DHL pilot still got himself into trouble by following the TCAS instruction. We could end up in the same trap where pilots "analyse" GPWS warnings during an approach.
I did have a TCAS RA once during cruise (FL350, European airspace) and since it was an opposite (uncontrolled!) fast military traffic, our TCAS didn't have time to give a "TRAFFIC, TRAFFIC" warning and we were issued with the "DESCEND, DESCEND" warning immediately, accompanied by the controller "screaming" a lateral avoidance vector at the same time.
Condolences to all involved and please also think about that poor ATCO and what he/she must be going through. :-(
In any case, it is an accident which should have us all reflect that even in one of the best controlled airspaces with all the modern airborne equipment etc. we still need to be scanning that sky or at least scanning the ND continously for suspect TCAS targets in order to have as early a warning as possible of potential threats.
Another thing which I hope will *not* happen after this accident is that pilots will become wary of following TCAS RAs if it transpires that the DHL pilot still got himself into trouble by following the TCAS instruction. We could end up in the same trap where pilots "analyse" GPWS warnings during an approach.
I did have a TCAS RA once during cruise (FL350, European airspace) and since it was an opposite (uncontrolled!) fast military traffic, our TCAS didn't have time to give a "TRAFFIC, TRAFFIC" warning and we were issued with the "DESCEND, DESCEND" warning immediately, accompanied by the controller "screaming" a lateral avoidance vector at the same time.
Condolences to all involved and please also think about that poor ATCO and what he/she must be going through. :-(
Last edited by 320DRIVER; 2nd Jul 2002 at 09:18.
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Frequency Change
My initial thoughts here were (as reported as a possibility on Sky News) that the crew of the Tu154 had changed frequency before the warnings came from the German ATC. Did the Tu154 crew respond visually to the 757?
The warnings I assume came once the flightplan of the 757 had been handed forward from Swiss control. Please correct and forgive me if this is an unlikely cause.
Deepest sympathy to all those close to the unfortunate vicitms of this crash.
FS
The warnings I assume came once the flightplan of the 757 had been handed forward from Swiss control. Please correct and forgive me if this is an unlikely cause.
Deepest sympathy to all those close to the unfortunate vicitms of this crash.
FS
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Two questions........
1) Does a Russian built transponder give altitude/flight level information that a western built TCAS can use?
2) Why did the "authorities" tell us of large numbers of casulaties on the ground when no-.one was even hurt, let alone killled?
2) Why did the "authorities" tell us of large numbers of casulaties on the ground when no-.one was even hurt, let alone killled?
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Mid Air
Sincere condolences to all those involved with and affected by this tragedy.
Lets hope that there is no witch-hunt by the media and the authorities, but rather a full, accurate and worthwhile learning experience to all of us involved in the industry.
Let the next lesson be a less costly one.
Lets hope that there is no witch-hunt by the media and the authorities, but rather a full, accurate and worthwhile learning experience to all of us involved in the industry.
Let the next lesson be a less costly one.