For all the "old dawgs" - Procedural Control Q.

[1999]

When A/C is instructed to establish and mantain a Radial for the purpose of separation - is that A/C obliged to fly that radial until ATC instructs them to resume own NAV or Clears them DCT to a point or NAV ?

The dilema we discussed arose in the case when A/C is following its FPL (e.g. flying from point A (VOR) to a point B (Compulsory Reporting Point) and then to point C another CRP but which is not on the same Radial as the previous point B ) - so when the A/C is being "locked" on radial somewhere between points A and B - is it obliged to continue on the locked radial after crossing point B or it may turn direct to point C ...meaning following its FPL?

I always thought of "being locked on radials" as an analogy to "being locked on HDG" - meaning u follow it until you were told by ATC to resume own navigation or Cleared Direct TO ...
..Or was I wrong ?

Thanx

[India 99]

Not sure about the "Old Dawgs"
But for me . . . Yes No Yes

Yep . . your radial > for or to achieve Sep Criteria is yours until YOU say so.

No . . it may not turn without your say so (usual provisos emergency etc)
Just don't forget it and also ensure due consideration of other routes within the adjacent route structure both during the level change and the subsequent RON.

Yes . . I would agree, he or she, stays on the radial until you instruct otherwise.
AKA Rad Hdg if you wish to think of it in those terms.

99

[Sligu]

Yes, as soon as you turn off the radial then separation has been lost. And not all procedural controllers are old dogs (mid twenties).

[1999]

Thanx for the "reassurance" chaps
Of course "old dawgs" wasnt meant as an offence - thats why I put it in inverted commas ..
Again - thanx for your input

Cheers

1999

[2 sheds]

If you are tracking south, when you reach the DOC limit of the VOR, the radial is no longer reliable.

Indeed - and therefore. much more pertinent for the instruction to be "maintain ... radial until passing (level/position)"

2 s

[callum91]

Procedural Control

I thought of this question when I was trying to get to sleep last night:

What if you had two aircraft on Crossing Tracks (not radials of the same VOR)? How would you know when they have crossed?

Also, another procedural question (not related though): When an aircraft carries out a procedural approach, for example and NDB/DME approach, what information does the controller have to note on the FPS?

Regards

Callum

[Blockla]

What if you had two aircraft on Crossing Tracks (not radials of the same VOR)? How would you know when they have crossed?

Time/Distance calculations or simply pilot reports. You work out the 'area of lateral separation' (usually a distance from a waypoint(s); with all sorts of tolerances built in depending on what ground based or airborne equipment is available).

You work out the estimate for the points add a time buffer and then at that time they are clear.

You can use pilot reports to reduce the time buffers ie reporting clear of the area of Lat Sep; plus what ever distances tolerances you need to ensure integrity of the pilot report.

It all goes to hell when one or both a/c are off track.

"Rules of thumb" and "adding some for Mum" dominate this environment.

[DFC]

Telling a pilot to continue on a radial without limit may be unsafe due to the fact that the pilot could continue beyond the boundary of controlled airspace and/or the obstacle clearance requirements.

If I was in a non-radar environment and told to continue on radial XXX which defined the route portion between A and B, I would be seriously questioning the reason why I was not being permitted to turn at B.

I think that the safest clearance would be along the lines of;

A report established radial XXX (radial defines A to B)

B report establsihed radial YYY

When they both report -

A climb FLZZZ cross B flAAA (vertical separation) or above

That is what I would expect to see.

--------

What if you had two aircraft on Crossing Tracks (not radials of the same VOR)? How would you know when they have crossed?

Ask them to make a position report at the reporting point where they will cross. when both have reported, they have crossed.

[ferris]

Ask them to make a position report at the reporting point where they will cross. when both have reported, they have crossed.

This is not true. See Blockla's answer for the correct method ATCs use (ICAO Doc 4444 defines methods for ensuring lateral sep in the procedural environment). You need to add appropriate buffers.

[callum91]

Thank you - I've found ICAO Doc 4444 so I'll have a read of that...

[1999]

To DFC :

Let's say it's a bit "complex" case - because the timing is such - that by the time A/C no1 crosses point B established on R XXX, the A/C no2 is not yet Established on R YYY (which of course differs by 15° ) and therefore u have to "wait" for no2 to get it there - consequently no1 by that time has passed point B and has to proceed on given track until level crossing is achieved (Of course obstacle clearance wouldnt be a factor -talking about Upper airspace and the A/C remains withing the limits of controlled airspace at all times ) . Distance between points A and B is approx 30 NM and the A/C no2 is much faster than A/C no1.)


Cheers
1999

[DFC]

This is not true. See Blockla's answer for the correct method ATCs use (ICAO Doc 4444 defines methods for ensuring lateral sep in the procedural environment). You need to add appropriate buffers.

Ferris,

I said that they had crossed. I never said that they were separated.

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1999,

Ok I can see that it is not simple.

[tobzalp]

Wrong. They will have crossed when the tolerances have been met.