Mid-Air Collision over Southern Germany (merged)

[BEagle]

I do not intend to pass comment whilst the facts are still emerging. However, one observation I do have is that it is almost impossible in these RVSM days to know whether the FL you've been assigned is 'wrong way' or not. Gone, it seems, are the days of flying IFR semi-circulars based upon track in Class A airspace.

[arcniz]

This tragic accident seems to be characterized by a short list of ambiguities that were either unresolved in time or unsatisfactorily resolved. Perhaps readers will care to correct, amend or add to this list.

One can hope that it may be possible in the future to define or refine procedural and technical means to eliminate these and similar ambiguities to prevent a recurrence.


Ambiguity 1) Relative Position: The two aircraft seem to have been unaware of each other's positions, especially the details of same altitude and intersecting course, until and even after the TCAS alerts. So the crews were not prepped for informed avoiding action there and then in the dark night.

Ambiguity 2) Visual: The roughly right-angle intersection of aircraft tracks made visual contact a somewhat difficult scan at night until very close to the collision zone. Other than the assumption of common frequency guarding, I have not seen info that traffic advisories were called to either aircraft about the other.

Ambiguity 3) Timing: The flight crews evidently had no particular sense of urgency until at or near the time their respective TCAS alerts sounded.

Ambiguity 4) Resolution: The presumptively reliable TCAS information for DHL was unambiguous but turned out to be unhelpful. TCAS guidance in the TU is not yet as clearly understood, but by inference that it was opposite to DHL guidance, so it would also have been opposite to contemporaneous ATC guidance, creating a fundamental and unresolvable ambiguity for the TU crew at the critical decision moment.

Ambiguity 5) Remediation: In the last 25 seconds prior to the collision, none of the responsible parties (DHL, TU, and ATC) evidently had sufficient information to call off the disaster because information ambiguity existed at all three points of control regarding the T-25 manoeuvers and merging positions of the two aircraft.

[Semaphore Sam]

Following questions are just that; not in any sense implied judgment:

1. ARE THE RUSSIAN ALTIMETERS IN METERS OR FEET? (5th time?)

2. Do Russians still use radio operators (as was the case with the Delhi collision a few years ago) that 'translate' radio calls to non-English speaking pilots?

3. Granting tremendous improvement in Russian English; with the new RVSM flight levels (FL 360, 340, etc) possibly causing delay in understanding due to newness of numbers, AND having to translate these numbers to meters (again new numbers), AND possibly having to go thru a radio operator/translator, the possibility for delay in understanding & compliance is there. Combined with a late call by ATC for a descent, a possible chain exists. Again I say POSSIBLE; just speculation.

4. (6th time) DO RUSSIAN ALTIMETERS USE METERS OR FEET?

[Fox3snapshot]

AusATCO,

I am with you....bit my tongue but happy to see I am not the lone soldier.

Bindook was a little out of line...Bindook do you have access to the actual ATC/Pilot transcripts, radar tapes, CVR, Aircraft Despatch notes, WX info, blah-de blah-blah....and if the answer to any one of these questions is no.... then Bindook I am sorry you do not even remotely come close to being able to determine who is at fault and you can join the ranks of most of the speculating community until this is all officially released.

I have just as many (if not more) mates in the flight deck environment than the ATC environment, but ultimately for many years have enjoyed something in common with all......we are in the aviation industry!!!!!!! Therefore lets not bleat and complain about who should do what and when and who's fault it is, but get together (a big narly booze up would do it!) and resolve decades of unsolved issues!

There will be a chain of errors in this disaster, and remember on a daily basis any one of us could be a link in this chain....

Good better best,
Never let it rest,
Till the good is better,
And the better best!

[Alpha Leader]

Altimeters in Russian a/c

Semaphore Sam:

Traditionally, Russian a/c have had altimeters with indications in meters. I understand that the TU-154 involved in this mid-air collision was equipped with one, too.

[TopBunk]

Not trying to prejudge anything, but I had a similar incident in mid-1995 in the region of the German/Swiss frontier whist en-route from LGW_SOF.

We were at FL330 SE bound working Munich about 80nm NW of RTT NDB (if I recall correctly), when we got an instruction from Munich ATC to climb immediately to FL350 and turn left 50 degrees.

This was in a pre-TCAS 737-200.

The intruder was a Dassault Falcon jet westbound under Zurich control at FL330. It passed within about 1nm horixontally and about 800ft underneath as we climbed.

I believe that it was to be investigated by the German authorities, maybe someone can find the results and point to them (date of event 15/6/1995).


Condolences to all involved, there but for the grace of God...

TopBunk

[Ruslan]

To whose who seeking whenever altimeter in feet or meters

I’ve posted already, Tu 154 equipped with BOTH, further more this is absolutely NO FACTOR,
Check EUROCONTROL RELASE showing height monitoring status of Russian aircraft 1 HOUR before tragedy

Gathering all available information, I would admit we came close to what happened, considering extra (instructor) captain onboard of RA-65816

[Bigmouth]

Was it VMC or IMC at FL350?

[Standard_Departure]

Skyguide claims that it is within standard operating procedures to issue an instruction to achieve separation within 50 seconds of impact.....

If this is the case, we can expect that the first instruction issued to the T154 would NOT have included the words "Traffic Avoidance", "For avoiding action" or "immediately", and that the ATC would have transmitted the instructions in a cool calm and collected fashion......

What will skyguide say if these words are in fact spoken in the transmission.

[Fox3snapshot]

Lets talk about the altimeters, understand that the jets were both originally cruising at the same level (verified), regardless of what measuring system they were using!, the requested level change from ATC was minimal ie 1000'...enough to provide vertical sep. Under the new RVSM criteria if it was in fact being applied. Regardless of peoples perception and misunderstanding of the new RVSM standards this collision could have been at any flight level ie. below FL290 and the 1000' separation standard required would would still be acceptable regardless of where you are in the world.

The Tupolov operators were experienced crew and the flight level change (feet or meters!) was not a major issue. It should be noted here, for those not familiar, that most the modern jets are equipped with altimeters and/or squizzy LCD/analogue kit that represents both standards meters/feet, why you ask?? Well it isn't just the Russian/Baltic states that are doing business in these numbers, China also are still working in this format and the Cathay/Air Honkers/Dragonair lads and ladettes will be very familiar with this, and is it now a good time to mention the Americans still deal with Altimeter readings in Inches instead of Hpa/Mba,

When......oh when will this planet decide on a universal standard!!!!

List of Aviation measures...
Height in feet....ooooh ...and meters
Visibility in .....meters/Km
Area pressures...Hpa/Mba...and Inches...
Longitudal/lateral ATC Separation....in miles
Time....GMT/UTC
Runway separation....meters...and feet etc. etc. etc.

[ramsrc]

Tu-154 Dual altimeters

Further to what Ruslan has said about dual altimeters on the Tu-154. This photo from airliners.net shows them quite clearly on a Malev Tu-154.

[sponix]

CPB

"The incidents you list above, whilst certainly part of the communities TCAS learning process, are somewhat dated. To the best of my knowledge the issues raised have been addressed."

I hope the problems have been sorted! Can anyone be sure though and have *all* existing systems been updated??

"..So for erroneous altitude encoding to nail you, both ADCs have got to be in error by the same ammount, and become so at the same time. Highly unlikely."

Unlikely but *possible*.

"As mentioned above, it appears the b757 manouevred first. From reports above, and the crews call to ATC, a descent was flown."

The impression I got from the media was that the Tupolev strated to descend shortly BEFORE the Boeing.

"Someone else maintains that the t154 was also TCAS equipped."

Yes, BBC news stated that BOTH planes had TCAS.

"If if it was equipped, (and on and serviceable), then they will have been receiving a 'Climb RA'. They descended. TCAS should still have been able to ressolve the situation by issuing a reversal to the b757 UNLESS it was pre version 7 (see my post above)."

Anyone know if Russian TCAS systems have been updated to the latest software?

"Now, pure speculation I admit, but lets say you are flying a non TCAS aircraft and you suddenly realise that ATC want you to descend urgently. As you commence your descent, you hear another aircraft saying 'TCAS Descent'. What goes through your mind?"

I don't like to think..

Sponix

[Fox3snapshot]

Please check Ruslan's post to answer the altimitery questions:

Ruslan:

To whose who seeking whenever altimeter in feet or meters

I’ve posted already, Tu 154 equipped with BOTH, further more this is absolutely NO FACTOR,
Check EUROCONTROL RELASE showing height monitoring status of Russian aircraft 1 HOUR before tragedy

Gathering all available information, I would admit we came close to what happened, considering extra (instructor) captain onboard of RA-65816 Ruslan To whose who seeking whenever altimeter in feet or meters

[Alpha Leader]

Summary of Facts so far and Questions

Based on official statements by Skyguide to date (and they are far from being unambiguous and complete), there are three major questions hovering:

Why were two a/c which entered Swiss-controlled air space on intersecting flight paths allowed to proceed for so long at identical flight levels?
In the case of the TU-154, the time elapsed since entering Skyguide’s air space was around 4 ½ minutes (based on Skyguide’s on press releases, and in the case of the B-757 it was 7 minutes.

Why did the Russian crew not respond to the first set of instructions?
In combing through statements released to date, there has also been no clear evidence as to whether the Russian crew ever positively acknowledged the second set of instructions (issued about 25 seconds prior to impact) – other than to initiate a descent.


What was going on at Skyguide’s Control Centre?
With their own conflict detection system down and only one controller on duty (the other taking a break), was there possibly a sudden case of task saturation (or the opposite – a false sense of “no problem”)? Apart from the two a/c that eventually collided, there were only another three a/c in the sector at the time. It has been confirmed that the B-757 crew radioed to Zurich ATC that they were diving based on their onboard TCAS, so – given his previous/simultaneous instructions to the TU-154 to descend, one would have expected the controller to immediately instruct the B-757 crew (with whom he was positively in contact) to climb.

We once again face the sad fact that an accident is rarely the result of one single action, but an unfortunate chain of events.

['%MAC']

Wow, there’s a panel that could use a human factors engineer. I suppose the altimeters (3 of them visible in the photo) are clustered around the RMI? Which one is in feet and which in meters? Two are drum pointer types, and the odd one is the 3 hand pointer to the right of the RMI, but they don’t seem to be labeled.

[ramsrc]

%MAC

This photo, again from airliners.net, shows a Tu-154 in flight. The two altimeters above the RMI appear to show feet (right hand instrument) and meters (left hand instrument). Not sure where the third one fits into the scheme of things though, perhaps provided as a backup unit?

[Oldjet Jockey]

If the times quoted in previous posts are correct, I am amazed that a controller accepted the hand over of a flight on a crossing track at the same level as an aircraft already under his control when the time at crossing point was exactly the same and this only five to six minutes before the crossing point. Absolutely no longitudinal separation and very little time to resolve the confliction. Questions need to be asked on the application of co-ordination procedures between the various ATC units

['%MAC']

Ramsrc

Thanks, that clears it all up. The 3rd looks like meters also.

(They're not exactly holding altitude)

[Alpha Leader]

Oldjet Jockey:

Good point. In particular, the flight path of the TU-154 (heading for Geneva) was to take this a/c over Trasadingen (only about 10 - 15 nm W of the collision site), at which point it would have been directed to 35000 feet anyway, this being the standard FL for this route. The question is, indeed, why did ATC not direct this a/c to 35000 ft immediately at hand-over?

[GEENY]

ID 90 and others,
In the Inex-adria vs Trident the DC-9 was alreadyabove the Trident level when instructed to descend.
If the TU was physically above the 757 the TCAS RA make sense (the altimiters could have been showing the same alt).