Altitude restrictions

[batty]

On the Lorel arrival to Stansted the procedure has an altitude restriction of FL200 at PEDIG and FL150 at CLIPY. We are usualy cleared to decend 200 by PEDIG and then handed over to 119.77. As soon as we check in we are invairably recleared FL150 by CLIPY.

My question is does the previous 200 by PEDIG still apply or has it been superceeded by the 150 CLIPY?

At the moment I still make the 200 at PEDIG and then slow the decent to make the 150 by CLIPY. If however the PEDIG restriction has been superceeded I could just adjust imediatly to make 150 at CLIPY and keep a continuous decent profile. What are you ATC guys expecting?

Ta!:ok:

[ukatco_535]

If you have been given a new level instruction it supercedes the previous one, i.e. the FL200 by PEDIG is no longer a restriction.

However the controller may say to you "Descend FL150 level by CLIPY, cross PEDIG FL200 or below" if he or she wishes you to fulfill the original clearance.

If they have not reiterated the "cross PEDIG FL200 or below", then you can descend at any rate, as long as you make the new clearance i.e."level by CLIPY"

[Vlad the Impaler]

Yep as UKatco 535 says. There was a lot of debate about this point on here a while back with some varying views from controllers. The ones who disagree with the above are wrong, as with any clearance, the issuing of a new one supercedes the last and any conditions required must be restated.

[batty]

Good news thanks but one more question in which case why the initial Pedig restriction if its immediatly overuled by the next sectors Clipy restriction? Why not just 150 by Clipy?

[duece19]

Batty

Im going to give this a try, Im not a controller but a pilot who spends to much time with atc simulators.

If Im not totally wrong the London TMA sector BNN (119.77) "ownes" from FL195, while S27 (130.92 i think) ownes down to FL195. Airplanes on Lorel arrival will leave sector 27 through its vertical boundary. Now to meet the CLIPY restriction airplanes need to enter BNN sector in good time for controller to be able to accomodate its further descent. So therefore a ROGBI is inserted in the arrival for S27 to be able to transfer airplanes on to BNN.

Now, this is just my guess, but I hope its correct.

Cheers / Duece

Edit: My brain is like a mushroom after the weekend

[Vlad the Impaler]

A more simple answer is that we are a little lazy, actually that isn't true, we are a little busy !! when you are given descent FL200 Level PEDIG and then the TC Midlands controller transfers you to TC N. What North should really say to you is "Descend FL150 level CLIPY, cross PEDIG FL200 or below". When you have sixty + ac to talk to in an hour that involves a lot of extra words which although technically so, are not practically necessary.
The standing agreements between sectors include a bit which says the receiving sector will not issue any instructions which will affect the expected climb/descent profile set up by the previous sector. By removing the previous level restriction this is no longer guaranteed. In reality it often make little difference but there are cases where the level restriction is required to separate traffic from other routes (ie L9 inbounds to TMA from Bristol sector FL140 40 before OCK, if this is not met it can get very embarassing against the gatwick inbounds southbound at FL150 which transit OCK airspace but do not work the sector !!). In these cases I would expect that the level restrictions are more strictly applied.
Hope that answers the question !!!!!!

[5milesbaby]

NATS have recently re-advised ATCO's that by issuing a level clearance, it will supercede anything already told to the pilot in relation to level by's unless they are re-itterated.

The Standing Agreements are in place so that as a receiving ATCO you can be sure that the clearance will be met by, in your example, PEDIG, and therefore other aircraft in the sector can be climbed/descended relying on this.

If the transferring controller cannot make the restriction then a quick call alerts the receiving controller to the matter and an alternative solution formed if needed.

If the receiving controller has no traffic against your descent then they will not re-issue the first level restriction.

[Barry Cuda]

Sorry to be pedantic but..... :ooh:

119.77 is TC North West Deps, not TC BNN (121.27)

TC Midlands do the descent to FL150 lvl Clipy before handing off to TC NW Deps.


Other than that a fair stab from deuce19, so 1 house point for you!!!:cool:

[ukatco_535]

Batty,

I will try to give you a succint answer to your 2nd query; bear in mind I do not work the airspace you are on abou

A lot of sectors are split vertically as well as horizontally, and to give controllers a fighting chance, the majority of A/C which transit from one sector to another do so on 'Standing Agreements' this reduces the need for individual coordination between sectors, so cuts down on phone calls (imagine if a controller had to make a call for every A/C - it would be impossible to shift the traffic).

As a result, the most common and often used routes are subject to these standing agreements (i.e. known levels that A/C enter or exit sector to sector). These agreements allow some degree of separation. For instance sector A may give A/C to sector B at FL100, whilst sector B gives opposite direction A/C to sector A at FL110. This means that we can plan ahead and know what the majority of A/C inbound are going to be doing (it also means that until we start controlling you, you are safe!!)

If the sector A controller received an A/C from sector B at FL110 and it had nothing to affect it, then they could give it a further clearance immediately, if it suited them tactically.