Descent clearance
Per Ardua ad Astraeus
Joined: Mar 2000
Posts: 18,575
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From: UK
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................................
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................................
Joined: Apr 2005
Posts: 260
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From: uk
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.........
"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.........
Joined: Aug 2000
Posts: 836
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From: Costa del Swanwick
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.
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.
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.
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.
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Joined: Jul 1997
Aviation Qualifications: PPL
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From: Europe
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.
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.
Joined: Jun 2000
Posts: 683
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From: UK
Originally Posted by 1985
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.
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
