Descent clearance

[flyer4life]

I'm sure this has been asked before but I keep getting conflicting opinions from pilot colleagues.

Say I'm at FL380 with 20 miles to run to my descent point when I get the following instruction: "Descend FL290, 2000fpm or greater". So this takes me below my ideal descent profile.

As I'm passing FL320, I then receive "Descend FL220" from the same controller. Now, I understand this is a new clearance which replaces the old clearance, so I can descend at, say, 1000fpm, to get back on my profile.

But some would say you should maintain 2000fpm until FL290. Who's correct, and is there a written reference?

Many thanks! :ok:

[CamelhAir]

Any clearance supercedes the last. It's somewhere in the UK AIP.
In your example, the controller needs to reiterate the rate, otherwise it's all yours.
Of course, you could always ask the controller if in doubt......

[javelin]

To be totally pedantic, each controller or each clearance must indicate whether there is a constraint.

If you are cleared 270 by LIFFY ( my personal Nemesis ) and as you approach, they throw you to MAN who say descend 190, you do not have to make 270 by LIFFY and can maintain 500 f.pm. until you regain your profile, provided the MAN controller does not re iterate the constraint.

Now, this is not a flame issue with ATC, it is a really pissed off attitude to the people higher up who issue block standing agreements without concern to our standard profiles and normal descent rates.

It is high time the front end and the ground end got together more and achieved some better BSA's :(

[Jumbo Driver]

Any clearance supercedes the last. It's somewhere in the UK AIP.

This is a perennial and you are quite correct, CamelhAir.

I don't know where in the UKAIP it appears but it is confirmed here (http://www.levelbust.com/downloads/srgfodsafety_leaflet_rtf.pdf), at the top of page 4.



JD
:)

[flyer4life]

Thanks guys, I'll have that SRG leaflet handy next time the bloke in the LHS argues this one with me :E

[hotmetal]

I don't recall receiving the 2000'/min type clearances in the UK very often so I don't see how the UKAIP will help. This is a speciality of Germany and more recently Maastricht. Have you had this clearance in the UK? I can only remember it once towards Biggin when asked for 270kts, 2000'/min and level by Tiger.
Anyway as far as the general point goes this has been done before and the answer is that if the controller doesn't repeat the restriction of ,say, be level by Saber then the restriction no longer holds. That is the letter of the manual as I understand it. However, I have read here that while that may be technically correct it might actually be useful just to comply with it anyway in case the controller has not pedantically stuck to every T crossing and I dotting routine required.

[fireflybob]

However, I have read here that while that may be technically correct it might actually be useful just to comply with it anyway in case the controller has not pedantically stuck to every T crossing and I dotting routine required.

My thoughts entirely! Also while we are on the subject these level restrictions are a limit and not a target - surely better to be down a few miles early rather than miss it by a few miles?

[DTY/LKS]

Javelin, if you do what you say at LIFFY then you could end up in the brown stuff.

The standing agreement issue has been talked about loads before on other threads. Although they are restrictive on you guys, they are there to facilitate the flow of the traffic to aid everybody.

In your example, the ATCO at Shannon Centre has told you to descend to FL 270 by LIFFY. This gets you beneath Lakes airspace and into Manchester Area Centre's IOM sector. The Shannon ATCO will monitor your rate of descent & if it looks like you are going to make the S.A then he will transfer you to the IOM ATCO.

Now here is the tasty bit.

The IOM ATCO descends you to FL190, therefore the restriction that the previous ATCO gave you still applies as it is not that ATCO that has given you a new clearance. SO the clearance of FL270 at LIFFY still applies. If you do not meet the standing agreement then this causes a lot of co-ordination betwwen sectors as you will be entering someones airspace that you are not permitted to be in.

Best scenario - the ATCOs co-ordinate your descent if it is safe to do so.

Middle scenario - you may have to make an orbit in your present position to get the height off to make the standing agreement.

Worst scenario - there is a Mil Crosser 10nm east of LIFFY co-ordinated thru at FL280, because you should be at FL270 by LIFFY. Could be messy.

If in doubt, and the same goes for anything else, ask the ATCO.

[BOAC]

DTY/LKS - while I am in full agreement with your sentiments and advice to 'check' if in doubt, it looks as if SRG and you are in disagreement. From the link given above (p4) Similarly, if the original clearance included a restriction, e.g. ‘cross XYZ FL180 or below' then the issue of a revised clearance automatically cancels the earlier restriction, unless it is reiterated with the revised clearance.
Maybe you need to raise this issue formally? If I recall all the previous threads correctly on this they all agreed with the SRG.

[PPRuNe Radar]

The IOM ATCO descends you to FL190, therefore the restriction that the previous ATCO gave you still applies as it is not that ATCO that has given you a new clearance. SO the clearance of FL270 at LIFFY still applies. If you do not meet the standing agreement then this causes a lot of co-ordination betwwen sectors as you will be entering someones airspace that you are not permitted to be in.


Like BOAC says, this is not what the CAA and NATS mandate.

There is no room for interpretation really. A new clearance will cancel any restriction in that part of the aircraft's profile (by that I mean a horizontal instruction won't cancel a vertical restriction and vice versa).

Otherwise there is no cast iron guarantee that the pilots will all do the same thing and no guarantee that an ATCO won't end up with egg on his face.

If you (as an ATCO) need a previous restriction adhered to then you either have to restate it, or else give an instruction such that the aircraft's minimum performance in accordance with the rules (500fpm climb/descent rate) will meet the restriction anyway.

[747dieseldude]

no written referance, just life experience:

we get these v/s clearances a lot over germany like:
"xxx, descent level 300, 2000 feet per minute or greater"
and when recieving lower level, while still in the descent, they often say something like:
"xxx, descent level 240, given rate"
sometimes they also have us report our given rate to the next sector.

On that subject, i have a question to you controllers:
if descending at 2000fpm, i am going to reduce it to maximum 1500fpm when i get to a 1000' from my cleared level. is it something you expect?

[DTY/LKS]

747dieseldude, yes we would expect you to slow your rate of descent down as you approach your cleared level.

BOAC and pprune radar, I totally agree that if an ATCO changes the clearance that he had previously given, then the new clearance supercedes the old one & all previous restrictions are cancelled unless reiterated by the ATCO.
I am saying that because the aircraft is being transferred between sectors, the receiving ATCO believes the pilot is complying with the standing agreement issued by the previous ATCO and then he gives his own clearance of FL??? In real life the restriction given by the previous ATCO is never mentioned as it is expected that the pilot is complying with it.

Any other ATCOs want to help me out????

[250 kts]

DTY/LKS,

Would like to help you out on this one but it doesn't matter who gave the original clearance. It is inherent on the initiator of the clearance to ensure the pilot will do as instructed. Just because the aircraft is transferred and given a subsequent clearance doesn't neccessarily mean the 1st restriction will be applied, although we would all hope that it would be.

Maybe it is time to put pressure on to get the AIP amended.

[Jumbo Driver]

Maybe it is time to put pressure on to get the AIP amended.

250 kts, I don't think that is necessary. Further to my post above, referring to the CAA Safety Leaflet - RTF DISCIPLINE - ADVICE TO PILOTS (http://www.levelbust.com/downloads/srgfodsafety_leaflet_rtf.pdf), I have now found an appropriate reference in MATS Part 1, at Section 1, Chapter 4, Page 4, which reads as follows:

7 Amendments to Clearances

7.1 When an amendment is made to a clearance the new clearance shall be read in full to the pilot and shall automatically cancel any previous clearance. Controllers must be aware, therefore, that if the original clearance included a restriction, e.g. 'cross ABC FL 150 or below' then the issue of a revised clearance automatically cancels the earlier restriction, unless it is reiterated with the revised clearance.

7.2 Similar care must be exercised when a controller issues a clearance, which amends the route or vertical profile of an aircraft on a standard instrument departure (SID). For example, 'Climb FL 120' automatically cancels the vertical profile of the SID. If the profile contains a restriction which provides vertical separation from conflicting traffic on another SID route, the restriction must be reiterated, e.g. 'climb FL120 cross XYZ 5000 feet or above', unless separation is ensured by other means.

7.3 Similarly, when controllers issue instructions, which amend the SID route, they are to confirm the level profile to be followed e.g. 'fly heading 095 degrees, climb FL 80' or 'route direct to EFG, stop climb at altitude 5000 feet'.
I am saying that because the aircraft is being transferred between sectors, the receiving ATCO believes the pilot is complying with the standing agreement issued by the previous ATCO and then he gives his own clearance of FL??? In real life the restriction given by the previous ATCO is never mentioned as it is expected that the pilot is complying with it.

I hesitate to disagree with you, DTY/LKS (as I guess this is your Validation), but I think in view of the above reference from your "Bible", MATS Part 1, you must be incorrect. I cannot find anywhere that says that, on change of frequency/controller, any previous restriction must be adhered to on re-clearance. Surely paragraph 7 above must be definitive, unless decreed otherwise elsewhere in CAP 493?

Surely the answer is that, on handover, the pilot will clearly be expected to continue to comply with the clearance given by the previous Sector; however, in the event of further amendments to his clearance by the second Sector, Paragraph 7 (above) MUST apply.


JD
:)

[skiesfull]

If in doubt, ask ATC for clarification immediately. Never assume!

[Jumbo Driver]

DTY/LKS, I have been re-reading this thread and your earlier posts and there is one further point I would like to put to you.

Don't forget that Standing Agreements are in MATS Part 2, which is confidential to you ATCOs and therefore neither addresed to, nor generally available to, us pilots.

The example you cite, transition from Shannon to MACC at LIFFY, requires descent to make FL270 by LIFFY - as you say to get under LACC Sector 7 above, which I understand has its base at FL285. I totally agree that failure of inbound traffic to make the previously cleared level of FL270 by LIFFY has obvious potential for conflict with either traffic in IOM Sector or Sector 7. Where I disagree with you is with your implication that the pilot has responsibility for complying with the Standing Agreement. He is not operationally aware of any level restriction as a Standing Agreement - he will (or should!) simply comply with the levels he is cleared to at each stage in the descent.

So, when you say ...

The IOM ATCO descends you to FL190, therefore the restriction that the previous ATCO gave you still applies as it is not that ATCO that has given you a new clearance. SO the clearance of FL270 at LIFFY still applies.

... I have to say I think you are absolutely incorrect.

If, on handover, the IOM Controller is in any doubt of the inbound's ability to achieve FL270 by LIFFY, he should reiterate the requirement. If he then issues a further clearance to, say, FL190 and does not restate the LIFFY constraint, then the restriction of FL270 at LIFFY can, quite rightly, be considered to be cancelled and I would suggest that Paragraph 7 (quoted above) clearly indicates this.

The point I am trying to emphasise is that it must be the IOM Sector Controller's responsibilty to ensure that the Standing Agreement is adhered to and not the Pilot's - Pilots are not aware of Standing Agreements per se.



JD
:)

[javelin]

Ooooo, I love this one Chaps :E

I sit on an airspace user group, do Fam Flights with MAN ATC folk and my Bro is a retired ATC Flight Checker.

What really pisses me off is the fact that in our carbon footprint, tree hugger, save a bit of gas world, we are being forced down early and at more and more restrictive levels - 270 at LIFFY is 4500 feet low on profile into MAN.

Now, if the great and the good of NATS and Shannon determine that this helps offset any holding at a low level, then fair do's - I don't have a problem.

I just wish that please, somewhere, the front end and the steerer's are actually discussing what each department want and can reasonably achieve to help us save fuel. 270 at LIFFY costs us, on an A330, about 500kgs of fuel on each and every descent, say 3 of our aeroplanes each day, 365 days a year, that is 547.5 Tonnes of fuel per year............... I'm sorry, when you multiply that up, it is an aweful waste of fuel just because the ATC guys say we have to comply.

You ATC guys and gals do a wonderful job, don't get me wrong, I just hate the inefficiency of 'the system' that drives it and don't know how or who to contact :ok:

[Pera]

DTY/LKS,
The restriction must be restated if you still require it. A new clearance cancels the restriction.
..


What really pisses me off is the fact that in our carbon footprint, tree hugger, save a bit of gas world, we are being forced down early and at more and more restrictive levels - 270 at LIFFY is 4500 feet low on profile into MAN.

Agreed, however any ATC intervention is going to cost fuel. Any level restriction, vector, speed control, holding, waiting for takeoff.... What is the safe alternative. I suggest that the other alternative is late descent and more track miles.

[1985]

Don't forget that Standing Agreements are in MATS Part 2, which is confidential to you ATCOs and therefore neither addresed to, nor generally available to, us pilots.



And don't forget that alot of the standing agreements are published in the AIP on the arrival sheets (STARs). Therefore if you are cleared for a LAM3A for example, i would expect you to make all the levels published on the arrival route. If i clear you to be FL250 by logan and the next ATCO clears you to be FL150 by saber then as far as i am concerned then you should still adhere to the previous restriction.

[skiesfull]

The LAM 3A does not have 'published levels', but advisory levels to be confirmed by ATC. There seems to be poor understanding of ATC clearances concerning descent restrictions. Perhaps CAA SRG should step in and make all clearances unambiguous in the R/T phraseology used?

[BOAC]

1985 - the discussion here really is not about the PUBLISHED restrictions but what we in the cockpit see as 'ad hoc' restrictions because they are not disseminated to flight crew on any published pages eg on STARS etc. Crews who 'miss' the Star levels are, well, just 'crews':) and that is really outwith this thread.

The 'restrictions'/early descents inbound the London TMA from the east are a case in point. None of them on the charts. We get them, try to remember them, and try to build them into our fuel/descent planning. If we get a 're-clearance' to a lower level................................

[skiesfull]

Taking the LAM 3A as an example of possible ambiguous clearances, surely the 'clearest' re-clearance would be as follows:-
"AAA123 descend to cross SABER at FL150, cross Logan at or above/below FL250"?
Maybe with RNAV SIDS/STARS, CPDLC and ADS-B such misunderstandings will be reduced or even eliminated - but by that time I will either no longer be on this "mortal coil" or be too old to care! In the meantime.........

[250 kts]

javelin,
The LIFFY restriction is about getting you into a particular sector in order to ensure you then make a subsequent Standing Agreement.This is the "network " effect taking place. I suspect if you were allowed to cross LIFFY on the normal profile the workload for S7 against Dublin outbounds and other Shannon outbounds would be so high as to reduce the sector capacity. You would then be the 1st to moan when you get a regulation and subsequent delay. If that were more than say, 20 minutes your company would then refile and I bet the additional fuel burn would be considerably more than 500kg!
The Operators have stated that throughput on the sectors is to be maximised and if that leads to inefficient profiles then so be it. It really is swings and roundabouts on this one. We will leave you high if we can and much of that area is dependent on the Oceanic traffic loading.
If you want to PM me and we'll talk more off line and I'm always available for a BGI fam flight to see the effects on your fuel burn.:ok::ok:

On the subject of the LAM3A it is high time we were allowed to just instruct you to descend "on the profile" as they have been doing at LAX for at least 15 years. RT loading is reduced and there is no ambiguity as to what is required from the crews.

[PPRuNe Radar]

Having the ability to use a ''descend on the profile'' would be great ... but how often could we give an aircraft a continuous descent clearance all the way to the bottom of the STAR ?? For quiet traffic periods it would be fine but we'd still need tactical freedom to give stepped descents for most periods of the day to ensure that vertical separation was given against other flights. Pilots would have to be educated that it will probably be the exception rather than the rule.

The advisory nature of levels in UK STARs (they are published for planning purposes - for use by crews in programming FMS, etc, and by Ops departments for fuel calculations) would have to be changed to some cast iron form of words which meant that pilots understood that they only followed the profile to the letter when so cleared and that they may also be given alternative descent instructions which override the STAR chart levels. Might be in the 'too difficult' bin as far as the CAA are concerned.

DTY/LKS

The UK wording came about around 10+ years ago since there was no clear statement before then about adhering to restrictions when given a subsequent clearance. The FAA had a system which (talking to FAA controllers and US pilots) was well understood and made it clear. The UK introduced almost word for word that same procedure, mainly because there was no need to reinvent the wheel when a proven procedure used in the busiest aviation country in the world already worked. It also ties in with ICAO procedures.

Personally I don't understand why it can still be misinterpreted. If an ATCO needs a restriction complied with then they have 3 choices. Say nothing until the restriction point is passed at the restricted level, or only issue a further clearance when the aircraft is guaranteed to make the restriction using radar Mode C data and an assessment using the minimum vertical rate published, or by restating the restriction as part of the new clearance.

The last option seems the simplest and most flexible to me.

Changing the UK procedure to a method which is 180 degrees out with the rest of the world is fraught with danger. The current procedure has been in place for long enough for everyone in the UK to understand and adapt their methods accordingly. If there is still misunderstanding in some quarters in the UK (ATC or aircrew) then I think that's what should be addressed by the CAA rather than amending something which does not require it.

[Jumbo Driver]

If i clear you to be FL250 by logan and the next ATCO clears you to be FL150 by saber then as far as i am concerned then you should still adhere to the previous restriction.

1985, I still think you would be wrong to expect me to adhere to the previous restriction if it was not restated on the subsequent clearance.

Let me put it another way. If your example above actually happened and I was not below FL250 by LOGAN after having subsequently been cleared to FL150 by SABER, I assume you would consider this to be an infringement. In your MOR, which rule or regulation would you allege I had not complied with?

I would cite MATS Part 1, Section 1, Chapt 4, para 7.1, which states:

7.1 ... Controllers must be aware, therefore, that if the original clearance included a restriction, e.g. 'cross ABC FL 150 or below' then the issue of a revised clearance automatically cancels the earlier restriction, unless it is reiterated with the revised clearance.

How would you counter this ?



JD
:)

[250 kts]

jumbo,

Just for once the driver is correct.:D:ok::)

[Jumbo Driver]

250 kts - thank you, kind Sir ... :ok:



JD
:)