Mid-Air Collision over Southern Germany (merged)

[Proceed As Cleared]

The Russian sources' claim that ATC clearance has to be given priority to TCAS RA is utter bollocks !

Looks to me like someone's desperately trying to blame the controller only...

[PFD]

CAP 579

States:

Action on receiving an RA (Resolution Advisory)

Pilots are to initiate the required to manoeuvre immediately, adjusting flight path, aircraft power and trim accordingly. Crew members not involved in executing this manoeuvre should confirm that the sky ahead is clear of other aircraft and continue the visual search for the established threat. They are to inform ATC asap of any deviation from an ATC clearance.

and

If pilots receive simultaneously an instruction to manoeuvre from ATC and an RA, and both conflict, the advice given by TCAS should be followed.

This is what I teach and shall continue to do so, because,

I WANT YOU TO LIVE.

Regards

[PFD]

30 seconds to go

I just spotted this in Ghostflyers post,

When you get an RA, you are 20 to 30 seconds from collision.

You should have already had a TA ('Traffic,Traffic') which is 35 to 45 seconds from possible collision.

Mode C and S transponders will also give you height information.

Displayed as the difference in hundreds of feet between you and the target, it also says + or - so you know if it's above or below.

If you both have Mode S the RA manoeuvre will be co-ordinated.

If the other aircraft has a transponder but no TCAS, yours still works.

regards

[vanman]

re "autopilot coupling to TCAS"

A typical TCAS II maneuver requires crew response to the initial RA within 5 seconds and G-forces of ± .25 G.This force is similar to that experienced when initiating an enroute climb or descent. Because of this G-force requirement, the response to the RA cannot be flown using the autopilot. The autopilot must be disconnected prior to responding to the RA.When the initial RA
is changed,the crew must respond within 2 1/2 seconds.

In the latter case:-

You are expected to initiate the change from <one maneuver> to <the opposite> maneuver within 2.5 seconds
using an acceleration of .35 Gs.

Source: www.honeywelltcas.com/pdffiles/tcas2guide.pdf

Don't quite see what they mean about the G-force being the same as that required to initiate an enroute climb or descent as obviously we normally initiate those through the autopilot, but anyway the timeframes for response (and increased G requirement for RA reversal) are worthy of note eh?

Cheers

[Ruslan]

Okay,
I'm just seeing repeatedly declaration (however should agree here) that we should follow RA even ATC saying others. But all of you refer to equipment manuals company rules etc, have you heard that no any legal regulations in that matter published in Russia (Russia not participate in RVSM neither any RVSM buffer area), from my understanding pilot should have some training to got RVSM able status operating within RVSM areas that is only a case that could got any training in part of TCAS procedures (I’m even not thinking about sim)…

Please do not consider guys working on western types and got excessive training before somewhere in Miami, furthermore on types which have TCAS onboard installed by default from manufacturer as standard equipment.

[EGGW]

Bottom line, obey TCAS commands when it comes to an RA. The crew of the Russian aircraft had a VERY confusing situation, and made the wrong choice.
My view at the moment, the Swiss controllers gave much too late instructions to descend. Why they chose to carry out maintenance of the STCA, and the procedures to account for that being U/S, seem rather inadequate right now. Why there was only one controller also on duty begs a question.

As you can see there is really no one single person/company to blame, a chain of errors.

[Standard_Departure]

Is it fair to say that there will be a "cause of accident" which may be a chain of events (albeit all within the skyguide "system")?

Furthermore, can it be said that if the pilot of the 54 had made a different call the accident could have been avoided (Note no blame)?

SID

[Nightrider]

At this stage, with all the available facts made public by now, I am almost inclined to see a very very sad problem here. The russian crew had all the equipment, and it also appears that this equipment worked as expected, and they simply failed to have the knowledge about this system.
Being in a position to listen and follow orders, they did as they use to do for as ling as they worked as an aircrew. The "intrusive" call of the TCAS created some confusion but was superseeded (in their views) by the ATC call to start decent!

It is not enough to have a little knowledge....

[Stupendous Man]

Re:TCAS vs ATC instructions


I know that if a pilot is supposed to inform ATC of any deviation from flightpath due TCAS RA, should it now be the situation where we are informed BEFORE this takes place and therefore should the TCAS parameters be changed to allow for more time.

I know that this could potentially end up with more TCAS related climbs/decents - but is this preferable to the tragic events of last week.

[mole]

Stupendous,

Surely the point is that ATC are supposed to stop it happening. If this fails then TCAS must be followed to solve the problem. In this incident the accident would not have occured if:

ATC had moved the tracks away from a collision path.

and when that didn't happen:

TCAS RA's had been followed.

Unfortunately neither occured so the worst possible result happened. The question is why.

TCAS is RIGHT - when it wakes up it is because something else has gone wrong. This can be as simple as inappropriate vertical speed or a total breakdown of separation. Whenever TCAS gives guidance we must follow it, even if that means we ignore ATC.

[garp]

The Russian crew decided to trust the instruction given by a human rather than the one given by a machine. Even if with hindsight they shouldn't have done it they just did what probably thousands of other pilots would have done. Those seconds when all three of them were looking at each other what to do must have been terrible. I also would like to add that in my experience the Eastern European pilots in general have a high level of profesionalism and frequency discipline. Something that can not always be said of the other European crews.

Garp

[Avman]

I'm not the technical type (leave that to the wife), but wouldn't it be fairly easy for TCAS to "talk" to the transponder, triggering a warning to ATC that the a/c is following an RA?

[unwiseowl]

Don't blame the 154 crew. Don't blame that poor controller. The blame lies with Skyguide management.

[Standard_Departure]

Avman,

I asked a question like that earlier in the thread, the simple reply is that there would be a requirement for mode-s (or in the future ADS-B).

It is obvious (and this accident is proof thereof) that ATC needs to know immediately when the TCAS commands an RA. It is also obvious that we cannot expect pilots to think about comms in an RA environment, there are just too many "more important" things happening during those moments.

There are 2 possible solutions;

The first is aircraft based, As soon as the TCAS commands an RA, it can (could) command the Transponder to automatically squawk a specific code (7400 ?) which would then indicate to the ATC that that specific aircraft is under RA navigation.

The second is based in the ATC Radar Software (maybe even as a function of STCA). The parameters used by TCAS (for RA) could be incorperated into the ATC software, so that when the RA would be commanded in the cockpit, and indication on the Radar display would show that there is a (potential) RA and indicate which 2 aircraft are involved. Bear in mind, this is simply 2 different computers that are using the same data, manipulated by the same parameters.

In addition to the above (whichever way it goes), the ATC would be mandated to take no (vertical) action until the "clear of conflict" call is made.

To repeat, It is painfully obvious that ATC needs to know when they have reached the end of their "jurisdiction", and pilot's can not be expected treat comms with any priority when they are possibly playing their last hand.

SID

[Stupendous Man]

Mole - I agree with what you say, and the situation should not have occured in the first place. however it unfortunately did.
But does the current TCAS system allow enough time for a controller (or pilots) to react to potne=tially conflicting advice.

We all know what pilots are supposed to do with an RA - follow instructions and tell ATC - but had any one considered the possibility of last weeks events happening? I think most peoples insticts (in any given situation) are to follow the human input rather than a similatneous computer one. Human nature. Especially if the human voice has an element of urgency or panic - which I am sure was the case in this instance.

[RaRadar]

Avman, Standard Departure

It is aready a feature of the Mode S transponder to initate a downlink message that contains the RA. The new Mode S radars that are starting to be installed in Europe will be able to extract this information. However, due to the radar update rate the delay will be between 0.25s and 10s.
Before this information can be presented to the controller the radar data format to the ATCC will need to be upgraded as will the display system. The move by Eurocontrol to impliment Mode S Enhanced Surveillance should make this happen.

RR

[Shagtastic]

A TCAS command surely has absolute priority over a conflicting ATC instruction because even the ATC instruction could be a malicious transmission from some neandathol with an expensive toy.

So sadly who is too guarantee the validity of what you hear over the radio.

[Avman]

SID & RaRad

Thanks for your comments and info. Certainly any delay over 1s would be too long and would defeat the objective. Mode S is a wonderful box of tricks. Unfortunately I guess that upgrading and susequent full implementation is probably still some time away for many ATC units.

[Blacksheep]

Just a word from an avionics engineer so don't get mad if this is impractical.

TCAS provides a Traffic Advisory (TA) to the crew when it detects a possible conflict. The crew are thus made aware of the conflict some time before a Resolution Advisory (RA) is issued and can locate the threat aircraft on their display. Both crews in this accident would have been aware of the conflict for some time. Might it not be good idea to have crews report Traffic Advisories to ATC whenever they occur? I don't know how often they occur , so maybe in practice, it would cause chaos to have every TA reported. Nevertheless, in this accident, if either or both crews had informed ATC of the conflict when their TCAS systems issued a TA, the controller would have had his attention directed back to the priority area in time to take appropriate action. A Resolution Advisory is meant to be a "Last Chance" warning. Although the TCAS design intent was for Traffic Advisories to give crews time to avoid the need for Resolution Advisories, in practice it isn't always possible for crews to visually acquire the threat aircraft.

Maybe it is now time to include ATC in the warning loop, but I suggest they be brought in at the beginning when a Traffic Advisory occurs, rather than wait for the Resolution Advisory to be issued. Its too late then - once an RA is issued, effective Air Traffic Control has already failed.

**************************
Through difficulties to the cinema

[Feather #3]

Even better, Blacksheep, if I see a '00' with an open diamond heading for me, I ask! It helps.

G'day