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-   -   Avoiding Action UK (https://www.pprune.org/atc-issues/141079-avoiding-action-uk.html)

panjandrum 13th August 2004 13:11

Avoiding Action UK
 
Seems like the CAA have listened to the troops again on this one;
(thats twice in living memory now!)

ATSIN 49

:ok:

Bern Oulli 13th August 2004 16:46


Para 4.3 Blah blah blah…However, the revised phraseology recommended after the study has been found to be less successful. The phraseology where the callsign is repeated was expected to mitigate the potential for “callsign clipping”; but in doing so, it appears to have introduced additional hazards that were not anticipated by the (Avoiding Action Working) Group.
My italics.

Question. Why were these additional hazards "not anticipated"? Was anyone who does or has done real ATC ever consulted? Who are these people? Have they not heard of the old adage "If it ain't broke, don't fix it"?

I suppose one must be grateful that the guys who actually talk to aeroplanes were listened to eventually. Perhaps this will start a trend?

Spitoon 13th August 2004 19:16

CAP 717 would suggest that the following were on the WG:
Mr M Cristofoli CAA Safety Regulation Group
Sqdn Ldr. K Dowling CAA Directorate of Airspace Policy
Capt K Elkington Business Aircraft Users Association
Mr B Johnston Guild of Air Traffic Control Officers
Mr T Mathers Guild of Air Traffic Control Officers
Mr A McCormick Institute of Professionals, Managers and Specialists
Ms F Merritt CAA Safety Regulation Group
Mr T Newman CAA Safety Regulation Group
Mr D Pake National Air Traffic Services Ltd
Capt E J Pooley British Regional Air Lines Group
Mr S Sharp CAA Safety Regulation Group
Mr D Stracey Airport Operators Association
Capt C Tiffin British Airways plc

Does anyone know any of them??

vintage ATCO 13th August 2004 20:05

Yes, several, but will not mention who here.

Jerricho 13th August 2004 21:02


Perhaps this will start a trend?
Unfortunately, I'm not holding my breath.

2 sheds 13th August 2004 21:09

If the above persons did, in fact, constitute the WG, I think that there would be serious doubts about what one or two could have contributed to this particular issue, whatever their expertise in other areas.

More to the point, looking at the phraseology - it also applied previously - having given avoiding action with an immediate turn, why do they all think that it is appropriate to (a) continue rabbitting rather that obtain a prompt readback of this essential and urgent instruction, and (b) pass traffic information using the clock code rather than cardinal points, the aircraft, at this stage, being thrown into an urgent turn?

AND ANOTHER THING!! WIH is all that change to Radio Check phraseology all about? (Adopts V Meldrew tone) I do not believe it!!!

Scott Voigt 14th August 2004 02:17

I recognize Derek's name in there and he always seemed to have his head screwed on correctly...

regards

Scott

Spitoon 14th August 2004 09:33

WIH is 2 sheds complaining about? How is the Radio Check phraseology changing? (With apologies to V Meldrew) I do not understand it!!!

Whipping Boy's SATCO 15th August 2004 07:42

The list is out of date. I believe that, more or less, the organisations represented remain the same, just that the job holders may have moved on.

Regardless, it seems like a pretty good representation of interested parties to me.

2 sheds 16th August 2004 22:17

Spitoon

Look at the latest amendment to MATS Pt 1 and the forthcoming new edition of CAP413 - then explain, please!

2 s

Spitoon 17th August 2004 16:14

OK - guilty - I really should read my MATS amendments!

And I agree with you.

LostThePicture 20th August 2004 08:40

From ATSIN 49.....

(A/c identity) avoiding action, climb/descend immediately to (level) traffic at (number) o’clock (distance) miles opposite direction/crossing left to right/right to left (level information).
So, let me get this straight. This so-called "Working Group" has decided that an additional "a/c identity" spoken after the "avoiding action" is SO UNTHINKABLY DANGEROUS that the phraseology simply HAD to be changed. But they're perfectly happy for ATCOs to use the instruction above, even though it was a contributory factor in a recent major accident.

If this "Working Group" actually did any "work" they would advise ATCOs to give avoiding action in the horizontal plane only, and allow TCAS to do the rest.

But hey, the ATSIN only remains in force until December this year. Maybe then we'll see some progress. :hmm:

LTP

Findo 20th August 2004 11:18

LTP your suggestion is a bit off the mark. Taking avoiding action in the vertical plane is often very effective and should remain an option for ATCOs.

What should not happen is ATCOs should not give any vertical avoiding action when a pilot has announced a TCAS manoeuvre. Unfortunately this does happen and the CAA know about it but are doing nothing to stop it. :mad:

Warped Factor 20th August 2004 11:55

LTP, did you ever stop to think that someone might have to give avoiding action to two a/c that don't have TCAS?

There are quite a lot of them out there at the smaller end of the market.

:rolleyes:

WF.

Spitoon 20th August 2004 14:58

Findo says

Unfortunately this does happen and the CAA know about it but are doing nothing to stop it.
MATS Part 1 SI 3/2001 says

On being informed that an aircraft is manoeuvring in accordance with a TCAS Resolution Advisory (RA), a controller must not issue control instructions to that aircraft which are contrary to the RA communicated by the flight crew.
At the end of the day, the only person who can stop avoiding action in the vertical plane being passed if it's not appropriate is the controller.

See, I do read some bits of the MATS!

niknak 20th August 2004 20:42

Spitoon

"At the end of the day

It gets dark.

how do you expect anyone to manage after that?:p

Findo 20th August 2004 22:32

Spitoon when a pilot declares a TCAS climb is that the end of the manoeuvre so the ATCO can assume it is safe to issue a climb instruction ? Well that is what is happening yet there are lots of examples where pilots have announced a climb and immediately followed by a descent instruction or some other change to the declared TCAS action.

The ATCO has absolutely no way of knowing that the last declaration by the pilot is what is actually being followed. There are now examples of instructions in the vertical given by ATCOs as avoiding action when an aircraft has already declared a TCAS manoeuvre.

Spitoon 21st August 2004 18:16

niknak - sorry, too deep for me! Unless you want the CAA to tell you what to when it's dark?

Findo, I take the TCAS climb call as the start of a manoeuvre over which I have little control. It hasn't happened to me often but it usually seems clear when the event is over and everything is back to normal. In the interim, I'll tell any other aircraft that might be affected about traffic coming their way. If it looks like a good idea I'll give a turn to the climbing traffic but I won't be surprised if the aircraft doesn't do it.

In many ways, a lot depends on the airspace you're working in. If it's Class A a TCAS RA probably means that something has gone wrong and not been picked up by the controller or any other alert system - if there are any. In Class G, which I am more familiar with, there can be any number of quite legitimate circumstances that trigger an RA. Some are adrenalin-filled, others are just part of the fun of Class G. But I think the two environments are very different as are the ways that a controller might respond to them.

Not a perfect answer - but not a perfect situation. I'm aware that issuing avoiding action in the vertical is not be a good idea when TCAS RAs are involved and I'll avoid doing so. But if in the circumstances it may resolve a conflict I'm glad it's available. A controller who doesn't want to issue vertical avoiding action has the perfect excuse for not doing so - but every controller is different as is every conflict.

Giles Wembley-Hogg 9th September 2004 14:14

It seems to me that that SRG set up their working group to look into the "Avoiding Action" phraseology because a number of problems had been found with the original format. I believe that these were primarily:

1. Callsign clipping, thus making it hard for the subject aircraft to know whether the manoeuvre was intended for it

2. The controller issuing the correct (but somewhat long) phrase, only to be answered with something like "... sorry London, was that for us". Typical causes of this would be flight crew distraction or inattention.

The Working Group thus introduced the new "double callsign" phraseology. The bonus of this is that point 1 above ceases to be a problem as the callsign cannot be clipped and point 2 above becomes less of a problem because there is more chance that the flight crew will hear their callsign.

It seems, however, that the "double callsign" phraseology has caused some problems. I would hypothosise that one of these is that the message is now so long and includes so many numbers that flight crew are failing to identify correctly the numbers they need - usually the heading.

A possible solution to this would be to issue the avoiding action like this:

"Avoiding Action, Avoiding Action, BAW123 turn left/right immediately heading XXX degrees"

or

"Avoiding Action, Avoiding Action, BAW123 climb/descend immediately FL XXX"

I believe that the use of the words "Avoiding Action" twice would get the attention of everyone on the frequency, thereby ensuring that the subject aircraft is listening. Additionally, since less numbers are used in the phrase, there is a good chance that the correct heading/level will be taken.

Once the initial avoiding action has been given to both parties (where possible) traffic information using the clock code can then be passed.

Of course I have not seen all the research material that the working group used in coming up with their solutions, but I think that my idea has some merit and I open it up for critical analysis from fellow Ppruners or the Woking Group themselves if they are among us.

G W-H

Jerricho 9th September 2004 18:12

Excellent idea G-W-H. Getting everybodies attention right from the start (and the correct tone of voice used as well ;) ).

I don't know how many times I heard people in the sim trip over the phraseology when it was changed there. This was when it was decided that everybody had to use the new way in their TRUCE/ETC.


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