Reaction to TCAS RA

[Nightrider]

Yesterday over Spain, busy time, ATC was handling about 12 aircraft simultaneously, several Spanish language conversations, suddenly a simple "TCAS RA" on the frequency.
Neither ATC nor any other aircraft reacting to the short and very unprominent call.
Since there was no further conversation regarding the incident we made sure it was not affecting us in any way, difficult as no info about location or altitude was available.
After about 1 minute the crew who declared the RA advised ATC that an ASR would be filed. There was no call of returning or continuing to any altitude.

Confused ATC responded that the clearance was FL230 and the conflicting one was at FL220, no mentioning of any action, no mentioning of any intervention, not showing any interest at all; as a matter of fact, we were under the impression that ATC was extremely surprised about the pilot statement and did not really know what this was all about.

TCAS RA is a very serious issue and needs immediate attention. The change in phraseology to today's simple "TCAS RA" can and does go unnoticed as seen yesterday. I doubt very much that this was the first event being handled or noticed like the one here.

Am I the only one who feels that the communication part as introduced about one and a half year ago does not provide the needed attention to attract everyone's focus on this very important issue?

Something similar to "PAN PAN PAN TCAS RA" would definately wake up more, if not all, who should get involved in the resulting action.

[anotherthing]

You should get an acknowledegment of your RA. Because of the nature of an RA, you might not get traffic information, to tell the truth it matters not an iota as you have to follow the action anyways.

If ATC was busy, as you state in your first sentence, then all they should have done was 'rogered' you.

The call you gave was "TCAS RA", that has not changed. Discussing/informing ATC that you are going to file an ASR on RT is not needed, nor professonal. In the UK at the very least, ATC must fill in a report for TCAS RA, and we expect aircrew to do the same.

Saying you will do so on busy RT does not help the ATCO, especially as a lot of the time it is a nuisance RA. Believe me, when as an ATCO you know you have done nothing wrong, and you hear someone call 'TCAS RA', it can be very confusing for a couple of seconds, as you check and double check the clearance you gave on your flight progress strips.

The call "C/S TCAS RA" is not unambiguous, and if said with the correct annunciation/urgent tone, i.e. more prominently than a standard RT call, it is more than sufficient for the job. Putting a PAN PAN PAN prefix is not a good idea.

The procedure works fine as it is, Spanish ATC were busy as you state, when it happened. Changing procedures in RT to cover either poor procedures, poor technique or the lack of response of one controller is not the way ahead. Addressing the problem by speaking to the controller/reviewing procedures is what should be done or inyour case filing an ASR..

I hope in your ASR you stated very clearly that you received no response from ATC and that in your opinion it was busy. Furthermore, I do hope you mentioned that Spanish was being used on the RT as well.

I see a lot of instances now from the ATC side whereby when someone has an incident, the 'cover your arse' attitude of management is to make up some silly new procedure that doesn't actually enhance safety, but of course it means if someone in the future has an incident management can turn round and try to pass the buck and apportion blame.

What should be happening is having a chat with the controller involved and ensuring they know what went wrong, why, and how not to let it happen again.

[Nightrider]

The point I tried to make here is that there was certainly a second aircraft involved. No second aircraft call on the frequency, perhaps it was on a different ATC-sector.
ATC did not at all react to the TCAS RA call, no confirmation, nothing. As mentioned, after the pilot who declared the TCAS RA advised about an ASR to follow, there was only a surprised ATC response, clearly showing that ATC was at that stage completely unaware about the situation and that the TCAS RA call was unnoticed.

This is extremely dangerous and in my opinion a result of the "tame" expression "TCAS RA". A more prominent call, accompanied or followed by i.e. a PAN PAN PAN would advance this situation to a higher priority with the needed adequate attention.

anotherthing, my posting crossed you one.

[anotherthing]

Nightrider

I have had a couple of TCAS RA's as an ATCO, in both instances, only one aircraft called it. One was a nuisance RA caused by high climb rate in the LTMA, the other was a 'real one', caused by an aircraft climbing to a FL on a low QNH pressure setting :eek:.

The worrying thing about the second one was it was the other aircraft that called the RA, the 'offending' aircraft did nothing!

In your example, I'd probably be more concerned about the fact that it seems ATC did not answer because they were

a) Too busy i.e. congested RT therefore easy for a short call to get lost
b) Mixing languages on the RT :=

I would hope that the ASR, when investigated, would show these as being factors, if they indeed were (I can't judge an even I haven't seen a relay of).

What should follow then (certainly would in the UK), is a rebriefing of the ATCO involved to ensure a timely splitting in sectors or reduction in traffic flow, and also hammering home the need to use one common language (maybe getting the Spanish to accept this would be too difficult though).

It sounds to me from your brief description, that the controller would not have had the capacity to deal with an emergency, which is very poor.

The problem with making it a PAN call is that an RA really is a difficult situation for an ATCO. We are not allowed to do anything though every instinct tells us to try to help!

Also, even the mere passing of traffic info to you may not actually be helpfull when you are flying the manoeuvre. Maybe a brief explanation when it's done and dusted but during the action, it is probably less confusing just to give a brief acknowledgemnt of your call :ok:

[Re-Heat]

The point I tried to make here is that there was certainly a second aircraft involved. No second aircraft call on the frequency, perhaps it was on a different ATC-sector.
Perhaps a light aircraft squawk, but without TCAS himself, or even another flight transmitting without "C". Many reasons why there might be no second response.

[EGPFlyer]

If this was the case then it wouldn't have been an RA, just a TA

[jb5000]

Departing Schipol one evening we were levelling at FL230, only just as we began to level off we saw 'pop up' traffic level at FL240 in our 3 o'clock.

We triggered an RA in the other aircraft, but we only got a TA, thus we made no call to ATC. AMS did call us to confirm our clearance as FL230, which we did, and we were then promptly handed over to a different sector.

Just because you had an RA does not mean that the other a/c did as well.

[Short Approach?]

As this thread so clearly shows, very few people are fully up to date on how and when the TCAS system works. THIS is the real problem.

[Airbus Girl]

Without double checking, I believe our SOP is to notify ATC when we are to submit an ASR for a TCAS RA. I think calling it flags the fact up to (particularly in this case) a busy ATCer and confirms the fact that we had an incident.

When we declare "TCAS RA" on the radio, an acknowledge is really useful because we know that ATC are now aware we are deviating from our clearance and hopefully will be moving airplanes out of our way. A response of "Roger, report clear" is useful, I thought it was now standard?

It is quite disconcerting when you get an RA and cannot hear the other aircraft but I have had one where the aircraft was on another frequency. We had to make further inquiries to find out basic info for the other aircraft to help with the report.

[woodpecker]

That lovely transition through Nicosia airspace, are the Greek's or Turk's controlling? Who knows...

Out of the blue "TCAS Climb". The response from Ercan, or was it Nicosia "Aircraft over NICAS requesting climb say again call sign"

"Don't bother"!!

[RYR-738-JOCKEY]

The bottom line here is that standard ICAO phraseology is not fully appreciated/understood by ATC in some parts of the world. It should be fairly simple..."C/S Tcas RA"...and then "C/S Tcas RA, Clear of conflict, resuming FLxxx". The same goes for an urgency call, or PAN-PAN. In some places an alteration to standard phraseology may be required. A typical scenario when in Spain is that if you expect to dip into final reserve fuel, you declare a PAN-PAN, if this is not appreciated you declare a MAYDAY.
However, I wouldn't necessarily assume that any ATCO down south would understand. So, applying the approach of "if he didn't understand, at least we did the right thing" -kind of attitude, will not do you any good. The basics of communication will always be to make sure the recepient has understood your message. If need be use plain language.

[sapperkenno]

Is it possible that ATC don't pay as much attention anymore, knowing that everyone has metal detectors on board, and crews are expected to take their own action in the event of coming too close anyway?

What is ATC's take on this? Maybe ATCers are briefed not to get involved, and this is interpreted as not needing to give a sh*t by certain (in this case, Spanish) individuals.

I'm just interested as someone who flies little planes at little-plane speeds, and uses my eyes for traffic avoidance. :\ :confused:

[Flight Detent]

As a side issue, but still part of the overall confusion issues here, what is it with the Spanish and the French with this unprofessional way of carrying on conversations in languages other than English...each and every time I've operated out of Paris CDG and ORY or Madrid MAD, there's always someone communicating not speaking English, which of course means that everybody else has no insight into what is happening, which is TCAS TA/RA country!

I was always very wary of ATC at both these places!

Cheers...FD...:\

[abra]

Splitting hairs,but what's a PAN PAN PAN? Surely it's a PAN-PAN, PAN-PAN, PAN-PAN if you're going to get the phraseology completely correct.

[Dan Winterland]

A TCAS RA is a real suprise to a controller who is either convinced he/she is doing his job properly, or terrified he/she are in the pooh for cocking up. Of the 4 I have had in my career, only one has been handled correctly by the ATC unit concerned.

And that was in China!

[ATC Watcher]

As this thread so clearly shows, very few people are fully up to date on how and when the TCAS system works. THIS is the real problem.

Absolutely correct.
I gave up correcting those posts, most of them appearing to come from PPLs or Microsoft FS experts (hopefully !).
As with everything nowadays, reading the operating manual would help.

[gone_fishing]

As a side issue, but still part of the overall confusion issues here, what is it with the Spanish and the French with this unprofessional way of carrying on conversations in languages other than English

It may be unprofessional, but it is perfectly legal for French controllers to use French aswell as English. Not the same for the Spanish, however.

[fmgc]

As this thread so clearly shows, very few people are fully up to date on how and when the TCAS system works. THIS is the real problem.

Not really true, as long as you follow your RA, you don't need to know how the system works!

[Caudillo]

splitting hairs,but what's a PAN PAN PAN?

Surely it's a PAN-PAN, PAN-PAN, PAN-PAN if you're going to get the phraseology completely correct.

Yes I'd be interested to know what is a PAN x3 too. For the life of me, unless it is PAN-PAN x3, I just can't think what you're on about.

Sleepless night ahead.

[anotherthing]

Airbus Girl

In the UK, the only response from ATC to a TCAS RA call should be "C/S roger".

It used to be "C/S roger, report back under my control" but this was changed recently.

The pilot is supposed to report to ATC when the RA action is complete.

ATCOs become passengers when a TCAS RA is anounced, some used to try to 'assist' by giving instructions in the horizontal plane, but that is frowned upon now as it could detract from the TCAS action and may even reduce the effectiveness of a climb/descent.

sapperkenno

With regards to ATC taking less interest in their job because aircraft have TCAS - nothing could be further from the truth!

TCAS is a last resort safety measure, in fact I have seen replays of a couple of instances where TCAS in the LTMA has caused one incident to escalate and cause multiple losses of seperation.

[Fanda_2007]

I plead guilty to all the non-pilot traits but, would pushing Ident after calling TCAS RA help ATC to identify the problem area quicker?

[blue up]

Hasn't Spain filed an RT variation? I seem to recall that TCAS Climb/Desc is still in use rather than the TCAS RA call. I stand (sit) to be corrected. I haven't flown through spain for several months.

[eidwanthony]

just to correct gone_fishing's point about it not being legal for the Spanish ATC to speak spanish, they are quite entitled to actually.


Spanish AIP

3.2 Mobile service
The aeronautical stations maintain a continuous watch on
the allocated frequencies during the published hours of service,
unless otherwise notified. Aircraft must communicate
with the radio stations on the ground which exercise control
in the area or sector in which they are flying. Aircraft must
maintain continuous watch on the appropriate frequency of
the control station and shall not abandon watch, except in
case of emergency, without informing the control radio station.
The languages normally used in the air/ground communications
in all the control centres and TWR/APP services of the
international aerodromes are Spanish and English.

Note the order of 1) Spanish and 2) English....

[gone_fishing]

I stand corrected. Thankyou.

[ve3id]

PAN PAN PAN was the urgency signal prescribed in the 1959 Geneva ITU Radio convention. I heard it used for may years, even up to when I got my ppl in 1981 and for years after that. It must have subsequently been changed by an ITU convention to make it sound more urgent and recognisable. Anybody know what convention/year it was changed?

[Gulfstreamaviator]

I think the next big accident will be because of the ERCAN lack of control control, this is the most dangerous "controlled" airspace I have ever flown thru.

I have had two RA in my life, one on departure from VNO, with a very high rate of climb, in the TMA....another story.

But the most serious was with ERCAN.

As an aside why is the EIRCAN frequency, not published as a caution / danger box on the relevent charts. It is no use as a seperate text page hidden in the void of the manuals.

When the accident happens the chart publishers, will be equally responsable for the deaths as the Turks in EIRCAN will be.

But I forget a Turk can never be at fault.

glf

[Blockla]

As an ATC I have been taught to acknowledge the TCAS RA Call with 1) Update pertinent traffic information if necessary (types clock reference intentions if known on traffic involved or nearby that the RA may additionally effect and 2)to ask the pilot(s) to report when they receive clear of conflict advice.

I had an RA recently with an aircraft descending to 1000 feet above another (FL330 and FL320), both got the RA and when they had manoeuvred down and up I believe they didn't get clear of conflict until 3400 feet apart and still diverging vertically (FL342 and FL308).

I've also had a 5 way TCAS RA in a holding stack, the top one descending too hard, the next 4 got TCAS RA descend as the one above dived on top of it etc following their RAs.

Both times, I had separation.

TCAS is great security blanket, great for level busts, but very annoying when it happens just because of vertical speed approaching the cleared level.

Personally I think TCAS RA is sufficient, the PAN calls would IMHO be overkill and perhaps just delay getting the right advice.

[Bomber Harris]

Let me be as specific as I dare on Pprune. just under 12 months ago I recieved an RA while descending in Manchester airspace medium level (about FL240). Of course, one of the most proffesional control centers on the planet. however, when I called the "TCAS RA" the controller started to tell me there was nothing to worry about, the other traffic was climbing to 1000 below my level. I didn't answer and followed the RA. ATCO's please comment on why I can still get a 'non-standard' reply after calling in an RA in one of our finest. With the quality of control i see at mach, I was disappointed. I would expect him to know that I had the a/p disconnected flying a relatively difficult manouver and that i was in no position to 'have a chat'. i would expect this from Deli control, but not the worlds finest. Any comments why this can still happen at our best control centers so relatively recently?

[anotherthing]

Bomber Harris,

The ATCO might have been trying to reassure you - a TCAS RA is still something that is irregular enough that it could cause consternation to the receiving crew.

However, as you state, you still have to follow the RA so the call is pointless and could actually cause confusion or distract you. There is no excuse for it from an ATC (UK) pont of view.

One other point though, again possible mitigation. You have some quite busy airspace in the UK, the ATCOS are, on the whole, very good at what they do. It is their job to be in control and 2 or 3 steps ahead of the game... it's what we pride ourselves in being able to do.

Bearing this in mind, the call 'TCAS RA' can be very disconcerting and confusing to an ATCO who thought they had everything under control.

The reply you mentioned, although it should never happen, might just be the ATCO verbally affirming/assuring themselves as much as it is a call to you...

If you can imagine, the ATCO has several aircraft climbing and descending, but the ones that will come into proximity to each other all have been given levels that maintain 1000' seperation. Then out of the blue one of those aircraft calls a TCAS RA... the ATCO should only acknowledge, no traffic info to be given, but they are only human and they might inadvertantly transmit something they shouldn't have, especially if the traffic situation is fairly complex and they've worked really hard to solve all the conflicts.

[GunkyTom]

Bomber Harris
I would expect him to know that I had the a/p disconnected flying a relatively difficult manouver and that i was in no position to 'have a chat'.

Why would you expect him to know that? I have been in ATC for 30 years inc mil/ Manch and wouldn't have the faintest idea whether the a/p was connected or not. As for a chat, it was hardly that.As previously mentioned, it was probably to reassure you that the 'confliction' was climbing/des to a safe level. Not correct procedure, I agree, but trying to keep you in the picture.

[anotherthing]

GunkyTom

To be fair, I would expect an ATCO, certainly a NATS ATCO, to know that pilots disconnect autopilot in anticipation of an RA and handfly the manoeuvre... it's part of the procedure... I can't remember exactly at what point they disconnect, but I do know that as part of NATS TRUCE training when they discuss TCAS, they should include the pilots actions. Certainly do at Swanwick.

Like you I was in the mil before joining and as a mil flyer (rotary) then an ATCO, I never knew about handflyng TCAS RA. But as a NATS ATCO I have had several presentations in the past 10 years and they all include the fact that the pilot handflies the RA.

Might just be that there is a bit missing from training as far as TCAS is concerned at MACC? Not having a go, just a very pertinent observation considering your remarks :ok:

[GunkyTom]

Anotherthing-

I am no longer in NATS but during my 10 years there we never discussed the A/P during TrUCE and neither do we now, however I am Twr/App and not speaking to a/c generally above FL140 if I can help it, so possibly we follow different curriculums .I stand by my comments re the poss reasons for the non standard reply though. It doesn't excuse it,but possibly explains the thinking behind it.:ok:


edited to add
Although it is obvious the A/P would need to be disconnected, it probably isn't the first thing to come to mind when you hear those dreaded words

[phil94028]

Well I'm a lowly PPL/IR in the US.

Kind of curious as to the RA criteria in terminal airspace. Here it is pretty routine to have 500 foot separation between VFR piston and transports.
It is much nicer if transport is the one on the bottom!

I had an airbus do an RA a couple of years ago. I was at 9500 assigned and he was restricted at 10000, maybe a mile or two away on converging paths. We were both talking to the approach controller and obviously on discrete codes. He'd be at 250 kts and I was maybe at 150.

I'd reported him in sight, but I think the transport crew were fussing setting up for the approach so didn't scan until they got the RA. Impressive pull up!

Do you guys always have to execute on the RA even with the conflicting traffic in sight? I think the answer must be no .. at least in the US.
How do you know for sure it's the right traffic?

[anotherthing]

Phil, you're last sentence answered your question. You should always follow the RA... to do otherwise could kill you (Uberlingen :()

[Paradise Lost]

While concurring with Bomber's praise for NATS controllers in the UK, I am still awestruck by the volume of traffic that New York Center keep apart during approaches to JFK/ La G/ Newark and Teterboro. Even with the TCAS on 6 mile scale, I still can't see a gap to fit through!
That said, I have had 3 RAs going in to TEB, all caused by the minimal separations that the SIDs/STARs require......often only 500 ft as mentioned by phil94028 in his post.
NATS and Eurocontrol have made several pleas to operators to ensure that they only approach their cleared alts/FLs at less than 1,000 fpm, in order to reduce nuisance RAs, but unfortunately the message is either being ignored or not sufficiently well promulgated to the rest of the world's aviators.

[gone_fishing]

You should always follow the RA... to do otherwise could kill you (Uberlingen http://static.pprune.org/images/smilies/sowee.gif)

Are you sure? I have put this question to an ATPL friend and he says not if the warning is a nuisance warning and both pilots are visual with it. I've also seen that ITVV video on the A330 and the crew get an RA, but because they're on final approach and are visual with him - they continue and ignore it.

I'm not currently a pilot, but I should be doing my PPL very shortly (in the Summer) and whilst this doesn't directly affect me yet - I intend to go on an do an ATPL and so am pretty interested in this.

[boeing_bananas]

Gone_Fishing,

The procedure changed quite a while ago, so now we always follow the RA. Don't forget this is a last-ditch warning to prevent an accident - ATC have failed to maintain separation and the pilots have failed to visually aquire the other aircraft soon enough. If you choose to ignore an RA because you're visual with the offending a/c, how do you know that you are indeed looking at the correct offender? Similarly, how do you know that the warning is a 'nuisance' warning - you might not have seen the other aircraft.

In short, follow the RA.

[GunkyTom]

Boeing Bananas

I would have to agree with Gone Fishing as to how the situation is handled by pilots where I work.

Certainly in a our airspace (D surrounded by and below A) most of our a/c make vis apps and I have yet to hear a TA/RA comment when they have been given traffic info and descend through or pull ahead of another to be No1, sometimes being only a mile or so apart. I can only assume when they have the potential confliction visual, they ignore or deselect the system.Also a/c low and slow tucking in to follow visually when the one ahead probably doesn't have him, nor need to from an ATC perspective.On a slight thread drift though, we regularly get 'have him on TCAS' which from ATC's pov means nothing as we can't base sep on that. However I am talking about the Approach environment and can see how my situation wouldn't necessarily fit in with all flying environments

[CaptainProp]

Welcome to Spain! :ok: You could have said MAYDAY TCAS RA no one would have reacted any different. Unless of course you know how to say it in Spanish...
Seriously though, my experience in Spain (and quite a few other countries) is that as soon as you stop using standard and daily used phraseology you can unfortunately not expect ATC (most of them anyway) to come up with a proper reaction or answer.

CP

[Nightrider]

Thank you very much for all the replies; it shows clearly that there is a system in place, including all the manifested procedures, and that it only works as good as the operator handles the issue.
Worrying is the fact that at both ends of the microphones and speakers are human beings with their own interpretations and reactions. It is clearly understandable that the adrenalin rush an ATCO experiences, after hearing the call, may lead to non-standard phraseology.....there is, however, also an adrenalin rush in the cockpit associated with the demand that any TCAS RA MUST be treated approriately.
Well, the situation I described did not affect my flight at all, but you put the coffee down and start scanning your system a bit closer.

[Bomber Harris]

guys thanks for the response. sorry i don't log on very often so it's a while ago that you gave me your comments. they were very informative.

surely atco's should be trained on what a pilot is doing when they call 'tcas ra'. could this be a failing in the training. if i am following an RA i really don't want someone telling me there is no problem, i mean, it's nearly a hint not to follow the RA. i am telling the atco i am following an RA so they know why i'm climbing instead of descending, I'm not asking for another instruction, or even a hint at an instruction. i just want procedure...then there will be distractions for me.

Your comments on the confusion from the atco who beleived he had everything under control are very informative and show an understanding of human behaviour. this i fully understand. i think i would react the same way now that you explain it to me. but i guess i would 'train' that reaction out of myself once i realised that i was causing furthur confusion for the pilot during a time when he has limited capacity.

i guess we all strive to be better, and as i said already, at least when i am in uk airspace i know i am dealing with the best. and one thing that makes you the best, is that you strive to get better

BH

[aprildavy]

As a developer of ATC safety nets equipment and a sometime pilot, it's also important to point out that normally the pilot is following ATC instructions while in controlled airspace. If a TCAS RA is indicated the pilot should report it and report when the TCAS RA encounter is completed - clear of conflict. Downstairs, ATC are hopefully watching their radar display. They may already be noticing the potential conflict and be about to issue avoidance instructions that are contradictory to the sense (climb/descend) of the RA instructions. Hence by notifying ATC, the pilot should not be given instructions by ATC, in order to avoid a conflicting set of instructions being given.

Remember also, that Short Term Conflict Alert (STCA) is fitted in many ATC units. This is a ground based conflict prediction system that uses radar derived positions and flight levels, calculated tracks and ground speeds, as opposed to TCAS, which is airborne. STCA may also be predicting the loss of separation and this is unknown to the pilot, until an instruction is given by ATC. On most systems, ATC do not know that the pilot is experiencing an RA. Some later systems have the capability to downlink the TCAS RA indication and sense and display this on the radar display, on the label information for the target. This requires a TCAS equiped aircraft, a Mode S equipped aircraft, a Mode-S radar, and a Mode-S capable ground surveilliance system. When the TCAS RA label is displayed, perhaps even at the same time as a STCA warnings, ATC now know that the pilot has been given an RA to follow, even if the pilot has not reported it.

All the information I can find is quite simple.
If the pilot is given an RA, he follows it, deviating from ATC clearance if necessary. He/She informs ATC. ATC monitor the situation. After encounter pilot reportes RA over and ATC will then manage the situation, since it's likely that the aircraft has departed from the assigned flight level.

Presumably airlines write these instrucitons into their operating procedures - not being a commercial pilot I don't know.

There's no need to call PAN PAN PAN, MAYDAY or whatever. The TCAS system is designed to give appropraite avoidance instructions. Obviously, if ATC, pilots, and systems never made mistakes, or took their eye of the ball, we wouldn't need such a system. It's just another safety net, like the height between you and mountains below.:ok:

[GE90115BL2]

1/ Aviate
2/ Navigate


then...............

3/ Communicate. :ok:

Why do people try to make this rocket science?

[A7700]

Do you know ,compared to the full number of reports ,the percentage of TCAS RA which occurs without any conflict.....? and sometimes with only one aircraft present...,

[ATC Watcher]

A7700 : not much I agree , but in a very few instances it saves the day. this is why so many still back up the system.

aprildavy : On a global scale :STCA is only avail in a handful of ATC stystems and radar cover far less than 20% of the world airpace . TCAS works everywhere. RA downlink is not a global solution.

Now , after Ueberlingen and the very near end of 677 in one go over Japan in 2001, where in both cases pilots decided to act, for different reasons, opposite to an RA, it open the eyes of some regulators that all was not well in TCAS training land, as a result procedures haver been made clearer and widely publicised to everyone.

The post here would indicate otherwise.

2 areas of misundersatnding howhever in many heads :

For Pilots :

If you have an RA, as a pilot you have to follow it , and advise ATC , and from that moment ATC CEASES TO BE RESPONSIBLE FOR YOUR ANTI COLLISION. So forget ATC and follow your RA.
If you decide not to follow your RA ( for whatever reason , you're in charge ) NEVER EVER manoevre in the opposite direction of the RA.

For Controllers :
an RA is not necessarily coming not because you made a mistake , (it can be , but it is not , and by large the majority of the cases) but because THE SYSTEM detected a risk of collision. Let the system and the pilots do their bit AND DO NOT INTERFERE.
If the clerarance you issued was safe , but a pilot manoever with excessive vertical rate and TCAS issue an RA, let it be. Who is to say for 100% that the pilot will stop at the level you instructed anyway?
TCAS is not there to ensure ATC separation, but to prevent aluminum to touch. In doing so it can distroy your plan and reduce your planned separation. But it is not your call.

TCAS is a last minute electronic safety net, nothing else. The least you interfere with it the better.If everyone would understand that, we will have made a great step forward.

[Dan Winterland]

Quote Phil from the USA: "Kind of curious as to the RA criteria in terminal airspace. Here it is pretty routine to have 500 foot separation between VFR piston and transports".

Two of my four TCAS RAs were in the airspace just to the North East of New York where you tend to cruise for an extended time at 16,000' in a Victor airway in just those circumstances. IFR traffic mixing it with VFR traffic at 500' levels. One RA against a twin coming the opposite way at 500' lower ended up with us in a climb and triggering another RA in an aircraft above us. The controller asked us why we had responded to the RA when we should have seen it would cause problems!

And before the usual US posters point out that it has always been that way and if we can'r hack it, we should stay out of the kitchen - or some other comment, I would like to point out that as a UK operator, we had no choice but to respond.

[jacek_flying]

I am very glad that you do respond to every RA,
I personally think that there would be absolutly nothing worse to have a mid air colision or even a close call and the best reason that anyone could come up with is that this is how things are done in this airspace.

I think that there is a reason why this equipment exists and each and every single RA should be followed religiously.