HDG of avoid traffic

[caucatc]

Does anybody know if there is any rules about how to give the heading when there is gonna make two aircrafts conflict or hit,because we are currently trying to find if we can make some regulations about it.

[BackAndForth]

Errr, "Don't" ?

[BackAndForth]

Unless of course you mean giving avoiding action to prevent a collision or loss of separation?

In which case it's something along the lines of:

[callsign] Avoiding Action, turn [left/right] immediately heading [xxx (degrees)], traffic [direction in clock code], [left to right/right to left/opposite direction], range [x] miles, [same level/x feet above/below].

[caucatc]

I did not mean how to say that ,but I meant how to issue the right heading to avoid the traffic ,as I know ACAS only give vertical guidance ,but we are trying to figure out if we can find a way to optimize how to give the right heading when two aircrafts are gonna to hit .

[reportyourlevel]

The UK CAA publishes a document called "Radar Control Collision Avoidance Concepts", available here (http://www.skybrary.aero/bookshelf/books/821.pdf). Perhaps this is what you are looking for.

[caucatc]

Ok, I will check that ,thanks so much for the help.:ok:

[climbwithagoodrate]

Issue a large heaing change, away from the conflicting traffic (best if you tell both), in a panicked tone - that should wake the crew up. Ideally, turns to the right, so as the captain can hopefully acquire the other aircraft visually. There is nothing optimal about it - do what you can to avoid a collision!!!

[AirNoServicesAustralia]

There is a school of thought that says not to give any headings once aircraft are responding to TCAS as it will degrade their climb/descent performance. Obviously the problem is that ATCOs don't always know the aircraft are responding to TCAS until after the action has been taken by the pilots (unless they have an advanced system that tells them).

Hard to sit there on your hands as the symbols merge I know but that is one school of thought.

[caucatc]

I have read the file which is provided by reportyourlevel ,can somebody read the page 13 ,item 6.13.7 ,it said both left or right is likely to move the aircrafts apart most quickly.
Don't you think plane01 turn right and plane02 turn left is better ???

[max1]

If it has got to the stage where you have lost your required separation standard, and a collision seems imminent, best advice is to give emergency traffic and suggest an immediate heading based on the surveillance available.

At this stage the controller has lost positive control of the situation anyway .

Every situation is different, you can't regulate a left or right hand turn, give your controllers a framework and intelligent regulations to work within, and give them the confidence to make a decision in this scenario.

This controller has just made a large mistake by allowing the two aircraft to get into this situation, they will only be paralysed by trying to remember the other regulation/rule when they have a critical time period to make a decision. If you regulate either a left/right hand turn or climb or descend instruction (Uberlingen), they may well follow your rule but is this the best way to resolve this unique situation?
A regulation/rule may make the ANSP feel happy that they have covered off a problem but you need to remember that the idea is not to let the planes hit.

Experience = that thing you get just after you've needed it.

In this situation, the one size fits all rule hasn't been invented yet and never will be.

[caucatc]

max1
You are right , but the reason I talk about this here is just wish to find a framwork and intelligent regulations to work within.Just wanna get some ideas.

[chevvron]

cauatc; are you asking for an example? If so, is it for :
a) Between two aircraft which are known to you ie both on your frequency.
or
b) One aircraft is known to you but the other is unknown?

[caucatc]

chevvron
Thanks for asking , we have examples both in one frequency and two different ,we just wish to figure out if there is a simple guidance about how to make a turn when there is a tendency for two aircraft colission.The link which is provided by reportyourlevel but I just do not understand the last sample as you can see my question in previous reply.

[BackAndForth]

Issue a large heaing change, away from the conflicting traffic (best if you tell both), in a panicked tone - that should wake the crew up.

Don't mess about, use the phrase "Avoiding Action" as well. That should definitely get their attention.

[ferris]

Don't you think plane01 turn right and plane02 turn left is better ??? No. :rolleyes:

[BackAndForth]

Depends if they're head on or converging/crossing tracks...

[Vercingetorix]

As reportyourlevel suggests the UK CAA CAP 717 covers most eventualities, i/e. left/right & up/down.

Give it a read.

Cheers :ok:

[caucatc]

ferris
Can you tell me the reason ? I think one turn left another one turn right will let those two separate faster.:confused:

[ferris]

Sure. My need to explain it shows you have no ATC experience and hence have been telling porkies.

The a/c in that scenario are about 3 nm apart, and are at FL410. At this point, you are pretty much screwed. The only possible thing that you might be able to get out, in the time available, is to turn the 'northbound' to the right to pass behind the other (by a very small margin, and only if the pilot were to act immediately. If this were a real scenario, the pilots would already be getting RAs). Airline a/c maneuver very slowly at high altitude, so the geometry of this scenario dictates that turning the eastbound right, and the northbound left (which is your question, correct?) would only ensure the conflict worsens. For you solution to be a valid way out, you need to have enough room (time) available so that the a/c can turn away from each other BEFORE the northbound crosses the westbound's projected path, and vice versa. Does that make sense?
If you don't have that time, then you help by trying to stretch the time available before one crosses the others path. This is achieved by turning them BOTH the SAME direction (as described in the advice).

[chevvron]

cauatc check your pm's

[caucatc]

ferris
Just as you mentioned ,let northbound one turn right ,the large turn radious may let northbound aircraft head on with westbound one ,do you think so ???If I turn northbound one left and turn westbound one right at the same time, I think it is better than a head on.:confused:

[Vercingetorix]

Ferris
Your comment: "Sure. My need to explain it shows you have no ATC experience and hence have been telling porkies" raises an attitude problem.

Why not help as opposed to being a negative git. Give the benefit of your worldwide experience to educate all.
The poster obviously has ATC experience but is perhaps limited to exposure to western ways of working.
Cut some slack and get off your high horse/donkey.

Cauatc, the CAP 717 document is the best that it available.
Good luck with your work.

Cheers:ok:

[caucatc]

Vercingetorix
Thanks so much , it seems that there is really a difference in the way that we work and western ways of working,but I will thinking aobut that.:ok:
Cheers
Jack

[welliewanger]

Hi Cauc,
Having read 6.13.7, I can see how turning both aircraft in the same direction may be less than optimal, however if (in the example diagram given) plane01 turned right 90 degrees and then plane02 did the same, the following criteria would be kept to a minimum:
- Reduction of separation (they wouldn't come close to each other)
- Duration of conflict (they would head away from each other fastest)

It seems counter-intuitive at first. I had to think about it. My initial reaction was to tell plane01 to turn right and plane02 to turn left. However, at the apex of these turns, the two aircraft would get very close.

I suggest drawing a diagram of the scenario as they have depicted in 6.13, then plot the routes the two planes would take.

HTH

[Piltdown Man]

Caucatc: You may also wish to consider that there are many pilots who will ignore ATC during a TCAS RA. After all, it was probably an oversight/foul-up in that ATC system the caused the RA in the first place. It is also my understanding that once I'm instructed to perform a TCAS manoeuvre, the system expects that I'll maintain my existing heading. I'll also wager that it would be a bugger for ATC to give any sensible headings to traffic involved in TCAS RA's.

PM

[ferris]

Give the benefit of your worldwide experience to educate all. Ok, I will, you sad old git. Perhaps in your haste to put $hit on me, you missed the body of my post, which was an explanation for the guy. It probably hasn't occurred to you, but if you look thru the posters history, he is more likely a software developer writing code for a video game or an add-on for Flightsim (or some such thing).
Do you seriously think that a person in the position of writing regulations or instructing in a college (as he/she has variously claimed) would have the knowledge base demonstrated here? Would seek answers on Pprune? Basic vectoring questions etc? Exactly how stupid are you? This is the internet, ffs, people can make all sorts of claims. I would prefer he just came out and told the truth. You, however, may continue to post your stupidity for all the world to see.

Welliewanger is correct. Given the disposition of the a/c in that diagram, if you turn the northbound left and the westbound right I don't believe the apex of the turns would occur until after they had passed (the first time). They would then be pointing at each other again (if they survived the first pass). Very high performance a/c such as fighters might be able to make the turns the poster suggests. Not airliners.

[caucatc]

ferris
Ok ,let me tell you the truth ,I am not any computer game writer ,I am a controller in BeiJing,China,maybe I do not know as much as you do ,it's ok ,but anybody was started from nothing,don't think you are the only one that knows a lot !!!!!!!!!!!

[tolgab]

I seriously doubt any controller in his right mind would turn two perpendically crossing aircraft in different directions to delay the cross unless one is supposed change level. That would put them parallelish so when and how are you going to resume them without changing level???

I think ferris is quite right, maybe a bit too harsh. How many of you actually bothered looking at what cauatc is suggesting and claiming he is a controller?

Either way caucatc, turning them left and right simply delays the cross but does not solve the problem. By turning them the same way, you push the one behind further behind and one in front further front. Draw it on a paper and you will understand.

ATC maybe handled different in different countries, but you cannot change the basic rules of physics.

[caucatc]

Thanks tolgab:ok:

[MontBlanc1]

Why have you not tried ICAO documentation, cauatc? Your country is signed up to them as are most in the world, and they provide invaluable advice as to what to do in an "unfortunate situation". They provide exactly the advice necessary that you are required to give if an aircraft states that they are following an RA. You should be able to easily obtain this from your employer as they will have access to it, and if they do not wish to give you this internationally renowned information, then email them (ICAO) and get it yourself, they are very understanding.

[Vercingetorix]

Ferris, as ever, you over estimate your importance, i.e. there is no haste to put $hit on you. It is a leisurely and ongoing experience.
MontBlanc1, excellent advice but perhaps caucatc may not be able to access all ICAO documentation, otherwise why scribble on here?

Ferris, someone, somewhere must love you but I think that it is time to rename you Ferret and put you back into the wild with your Weazel chum.

To infinity and beyond and, hopefully, back in time for a pint of Guinness.

CÉAD MÍLE FÁILTE (as opposed to my normal latin) to all readers with the exception of the Mild Bunch aka Ferret & Weazel

:ok: