To/From-Which one?

[SINGAPURCANAC]

Having consider pprune community as reliable one I would like to ask one question related to separation method minima in ICAO environment.
Doc4444,
Pages 5-5 and 5-6/7
5.4.1.2.a),b)c)
It is written and shown on pictures what is consider as "clear" but nowhere is written that both a/c should fly inbound or outbound facility/point!
So my question is:

Is it applicable in case when both a/c flying to facility/point ?

We have big dicsussion about this issue and since we working at PROC/ICAO enviroment we must have correct and based on relevant documents answers.
Youngsters are so nervous!
We will highly appreciate any relevant answer,or any suggestion what we should do in future to make situation clear.
Thanks,
SINGA

[Spitoon]

I presume you are asking about para 5.4.1.2.1.2 a), b) and c).

Although the text is very slightly ambiguous, common sense would suggest that as these are separation minima, whatever distance there is between the aircraft immediately after the separation is achieved will be greater than the minimum. Therefore, in each case that you ask about, the aircraft must be going away from the fix or intersection that is used to establish the separation. Note that the diagrams all show the aircraft heading away from the fix.

If the aircraft are flying to the fix or intersection you would have to achieve vertical or longitudinal separation from the point at which lateral separation no longer exists.

[SINGAPURCANAC]

he aircraft must be going away from the fix
Where is that exactly written?
Pictures represent such situation but nowhere is written.
Also I agree with your later explanation,but

How to persuade "opposition" that we are correct?

Apart from logic we need PAPER!
Anyway thank you for fast answer in this s:mad: night!

[Spitoon]

My persuasion would be 'These are separation minima, whatever distance there is between the aircraft immediately after the separation is achieved will be greater than the minimum'.

What do they teach them at training school these days?

[SINGAPURCANAC]

What do they teach them at training school these days?
this issue is even more interesting than my question at the beginning of thread.
List is endless but some of them:
1.You can't use Transition level!
2. You can't ask pilot for distance to/from NDB/POINT unless DME is co located with NDB/POINT
3. 5 Nm separation minimum( radar environment) is not applicable for head-on traffic
and so on....

[Wojtus]

Pictures represent such situation but nowhere is written.
Pictures are part of the rules, not only examples.

I was tough that both a/c need to be outbound from VOR/NDB/FIX.

[ATCO2]

Hi all,

I agree as well that both acft are to be outbound from VOR/NDB/FIX. There are some countries which apply different rules, one inbound and the other one outbound or even both of acft are inbound with longer distance required, for ex. in the USA as far as I know, but distance is 30 Nm for both inbound. It depends on NSA to determine what separation to apply.

One more thing, in the Doc.4444 it is written that DME is not only meen to ask when applying separation, now we may ask for GNSS distance as well, one or both acft.

I want to hear from others if you apply separation using GNSS and how to do it (phrase)?

BRGDS,

ATCO2

[SINGAPURCANAC]

Thanks for answers and opinions it helps us.
Some "experts" claim that it is more than clearly stated that only FROM is allowed. I could agree for NDB/FIX but for VOR there is space for discussion.
Because:
" Vor: both a/c are established on radials diverging by at least 15 degrees and at least one a/c is at a distance of 28km(15Nm) from the facility"
So,my dear experts-
radial from/to VOR doesn't tell us track of a/c,i.e. radial could be 180 but track at the same radial could be 180 or 360,
It means that you could say ,quite legally:
XYZ 123 report radial
XYZ123 radial 123
XXw 321 report radial and distance
XXW321 radial 155 distance 23Nm
XYZ123 climb/descent to.....
Because radials 123 and 155 diverging by 22 degrees which is more than required minimum and rule is applicable.
Regarding GNSS points common sense tells that there is no need for special phraseology.
it is pilot problem. Not ATC. You just tell to the a/c :
Proceed to POINT,report POINT.
If pilot is unable to determine position of such POINT i.e. is not equipped with GNSS equipment than he/she must say that there is no technical capability to determine such POINT and alternative instruction must be given.
We will appreciate any further discussion on this issue

[HEATHROW DIRECTOR]

I was brought up in the black art of procedural control and practiced it for some years in area control. The aircraft must be flying along the radial for VOR separation to work. You can't just get a position report of crossing a radial and you surely know which way the aircraft is flying so whether it's "to" or "from" is known....

[SINGAPURCANAC]

@ HD,
My fault. I didn't write that a/c must be established on radials. I considered but I didn't state it.
I hope that situation is more clear now.

[HEATHROW DIRECTOR]

So, they are established on radials - end of story.

[SINGAPURCANAC]

[QUOTE][ end of story/QUOTE]
In which direction? To or from?

[Wojtus]

I want to hear from others if you apply separation using GNSS and how to do it (phrase)?
Well, if you ask about RNAV procedural separation, the required distances are 80 miles...

I use "GNSS" distances very often in my airspace - stepped TMA with procedural control. Asking crew to report distance to NDB/FIX is the only way to make sure a/c will stay within controlled airspace while descending below FL100. I just say "Report distance ABC". And I never heard "unable" as a reply. If I will, the response will be: "Roger, maintain FL100 until ABC, expect descend in holding over ABC".

Returning to main thread:
There are situations when crew does not need GNSS to know distance from a beacon. Simple dead reckoning: overfly it, calcluate your GS (TAS + wind), count the time - you have distance. And that's the other reason both a/c should be outbound - those 4444 rules have been written in dark times with no GNSS at all.

[Neptune262]

What you ask is a valid question. Basically the answer is that ICAO does not make it clear and that every state should publish its own rules based on ICAOs.

If you look up the UK system for example it shows the minima for both aircraft travelling to, from and one in, one out from VOR/DME/TACAN (however uses 20 degrees as minimum, the use of 15 degrees is a whole other discussion!)

see Section 1, Chapter 3, page 5 of MATS Part 1 from the following link

http://www.caa.co.uk/docs/33/CAP493Part1.pdf

I do know of another ICAO based country that uses procedural seperation a lot. They do have rules regarding aircraft reporting crossing radials, and also less than 15 miles DME if the aircraft are further apart either established on, or crossing radials that are further apart than 15 degrees.

As you see you can get an answer dependant on the country the ATCO was trained in.

So if your country hasn't published its own rules then you have to stick with the ICAO grey ones. Sorry about that.