question for area controllers

[hooperfly]

Anyone feel like helping an ignorant 146 driver?

Does a restriction included in a clearance remain once a further clearance is given?

Example:
If I am cleared "Descend FL200, to be level 20nm before CLIPY", and then in a subsequent transmission cleared "Descend FL150, to be level abeam CLIPY", does the FL200 at 20nm before still apply?

Undoubtedly the answer is somewhere on my bulging bookshelf, but maybe someone can save me the effort...

[karrank]

In Australia the rule is thusly.

The F150 requirement cancels and replaces the F200 requirement.

If the controller wants BOTH requirements to apply he/she should have said,"Descend to FL150, ADDITIONAL REQUIREMENT to be level abeam CLIPY."

146 drivers here seem anything but ignorant Hooperfly, just a bit testy if you can't organise a descent clearance when the hair-driers start icing.....

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"Cut him off and call him shorty!" - Lorenna Bobbit (Patron Saint of ATC)
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[identnospeed]

hooperfly,

as an ATCO who does one of the sectors your example is from, I would say that I would expect you to still comply with the 200L 20DME Clipy restriction even when 150L Clipy is issued, eventhough this contradicts MATS Pt 1.
The reasons for this are (1) that due to R/T congestion I don't want to have to reiterate a clearance already issued by another controller, and (2) If you do not comply with the initial restriction, in spite of being issued with a new one, you MAY end up in the airspace of a controller who has no information about you...........obviously this is not safe.

IMHO, EXCEPT when a "level by...." clearance has been issued, the MATS Pt 1 requirement IS valid.

Hope this has been of some use.

INS

[Numpo-Nigit]

As usual, you'll find that if you ask a dozen ATCOs the same question, you'll get at least 13 answers!
As another en-route controller, albeit not valid on the sector in the example, I would expect the first restriction to be re-iterated as part of the re-clearance if it still applies. In the example given it would appear that the re-clearance to be 150 at CLIPY would allow descent below 200 before the 20DME point, thus effectively cancelling the "be level 200 20DME before CLIPY".

If the restriction is still required (as the previous reply seems to indicate), I would expect the re-clearance to be "descend FL150, level by abeam CLIPY, be FL200 or below 20DME before CLIPY".

Apologies to my Terminal Control colleague - there are always differences of opinion or emphasis from us in En-Route.

[RTB RFN]

N squared,

I agree with you - if there's room for doubt chuck it in again regardless of what the latest AOI, MATS1 or MATS Scrambled Egg Version says on a particular day - CDF always rules the day. Hell, there's people up there!

By the way BA146's are a dream to sequence - turn em into a fast lighty twin or a 737. Great working with you blokes.

[This message has been edited by RTB RFN (edited 01 June 2000).]

[identnospeed]

There maybe a difference of opinion (re: TMA and En Route) because apart from the odd co-ordinated overflight, EVERY a/c entering the TMA is descending to a level which is subject to a restriction. So maybe it is, as I said, R/T congestion which stops us repeating what you en-route guys have said.
Most a/c would receive a poorer service if we had to do as MATs Pt 1 says. More talk means less think !

INS

[vertigo]

Have to agree with identnospeed. Although the book says it should be reiterated in each new clearance, that takes up too much RT time. In very busy sectors it is not an option to reiterate the restriction in every clearance - there simply isn't the time.
The restriction is there for good reason, so follow it.
- mind you if it sounds quiet there's no harm in asking !!

[TinPusher]

It seems to me that if there is any doubt then ask the question!
However I would reiterate the initial restriction only if it was still required.

[Grandad Flyer]

Why doesn't the Lorel 1C STAR for Stansted have the level restrictions that you usually get? Such as FL 210 20 (or 25) miles before Midhurst? And the further early descent to FL 180, which is usually kept until past LHR? It would help those who are unfamiliar with the airport in their planning, as it usually means a higher fuel burn due to early descents.

[Ausatco]

hooperfly,

karrank is right. The second instruction in your example

If I am cleared "Descend FL200, to be level 20nm before CLIPY", and then in a subsequent transmission cleared "Descend FL150, to be level abeam CLIPY", does the FL200 at 20nm before still apply?

over-rides the first.

The second instruction says, in effect, "reach FL150 by abeam CLIPY"

That is a new requirement. It is not an addition to the previous requirement, it over-rides it.

If the controller wants to maintain the previous requirement he has to phrase his instruction to specify that, regardless of repetition and its workload/frequency congestion implications.

AA


[This message has been edited by Ausatco (edited 02 June 2000).]

[identnospeed]

ausatco,

I dont know what type of sectors you work, but your welcome to have a go at mine and talk at the required 19 to the dozen just to repeat what someone else has said.

I know of no-one working the London TMA who does. 5 watches of 25 TMA ATCOs per watch can't all be wrong. So maybe it is a factor of how busy a sector is, or an LTMA-only operating technique.

Sometimes the sectors are quiet enough for it to be done, however this then indicates to the pilots that they can expect such repetition EVERY time they come into LTMA. Absolutely not possible !

Almost invariably pilots comply with the previous restriction anyway, because the one I have just given them becomes tough to make if they don't. ie. FL150 level by Clipy can be challenging if you're still at FL200
with only 15 miles to run, which is exactly what the restriction used to be until about 18 mnths ago. Incidentally, the a/c needs to reduce from 300+kts it is probably doing to 250kts or less by the Clipy speed-limit-point.

With delays being a routine into LL KK and SS, most a/c appear to want to get down before the restriction so they can pull the speed in preparation for the hold and to allow absorption of some of the delay en-route to the stack.

I say again, this is the ONLY time I would advocate that a new clearance does not wholly obviate the need to comply with the previous one.

INS

[This message has been edited by identnospeed (edited 02 June 2000).]

[10W]

The repetition of restrictions brings the UK into line with ICAO procedures (even the USA !!). Given the large number of foreign operators into the UK surely providing this consistency is a good thing for flight safety ??

There's no denying how busy the London TMA is, I get held there regularly inbound to LHR, but if controllers don't have time to comply with safe procedures shouldn't the sector capacities be looked at and adjusted to a safe level ?

On the publishing of level restrictions on the STAR charts, this is expected to be carried out by London ATC soon as I understand. It was agreed in principle a couple of years back after an approach by the BALPA Technical Committee. And that will bring a new problem maybe......at least if our experience of publishing them in Scotland is anything to go by. "Scottish, does the MARGO level restriction apply to us today ?" on most RT calls :)

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10 West
UK ATC'er
[email protected]

[identnospeed]

Adjusting sector capacities is a great idea, but SRG has to have the b@lls to do something about it, because we can be assured that a newly privatised NATS is not looking to penalise its customers (the airlines) by applying restrictive flow measures.

PPP brings about profit-maximisation objectives which are not compatible with the application of draconian/safe? sector flow restrictions.

I wish that the few times a day when the sectors are quiet could be filled with a few more aircraft, just to help in the reduction of traffic spikes at the busier times. I'm sure this is applicable at every unit, but I'm positive nothing will be done about it.

Ref: USA procedures. I cannot comment on the en-route side of things, but the STAR which we flew (on a recent fam flt) had published level restrictions which MUST be adhered to...without further instruction from ATC.

A great idea, but it is very much a tunnels in the sky type of operation.......and we know how successful that was during the Evaluation Unit trials. i.e add a bit of weather et voila...carnage !

Again in answer to Hooperfly's original question, I would say that notwithstanding the MATS Pt 1 edict, it would be appreciated if you would still comply with the previous restriction. However, if its quiet please ask if it is necessary, as we do try to give continuous descent/direct routeings where poss.

INS

[This message has been edited by identnospeed (edited 02 June 2000).]

[KAPTAIN KREMIN]

The original requirement is valid for a problem requiring the aircrraft to be at (or below)FL200 by 20nm short of CLIPY. A new requirement with reference to FL150 would indicate either:
1. an amendment to the original requirement
2. an additional problem requiring an additional requirement
3.a relaxation of the additional requirement due to changed lateral separation tolerances
4.
5.
6.

etc.

The point is the pilot doesn't know and the controller probably hasn't got the time to spell out the complexity of the air picture.

Solutions - as appropriate:

1. use the phrase "additional requirement"
2. repeat the original requirement
3. use the phrase "cancel previous requirement, new requirement....."

Always works for me - keeps the big bits in the air and the little bits off the ground.


[This message has been edited by KAPTAIN KREMIN (edited 03 June 2000).]

[Numpo-Nigit]

I don't want to get into an argument with identnospeed and his colleagues in TC, not least because that will do nothing to enlighten hooperfly with his original question.

I agree that frequency congestion is an ever-increasing problem, not only in TC but in en-route and at some airports. However, the omission/abbreviation of standard RT calls is not the long-term answer - one day you could end up attempting to defend your point of view in front of a lot of unsympathetic lawyers!!!

To be pedantic, as I'm often accused of being, the original example DOES leave a lot of doubt. If, as identnospeed contends, the original clearance remains in force after the re-clearance to FL150, the aircraft should descend to achieve the FL200 at some point at or before 20DME from CLIPY, but is not authorised to descend below FL200 until after the 20DME point. Surely an aircraft, having been cleared to FL150, which levels at FL200 "unexpectedly" is not beneficial to TC or en-route (nor, indeed, to the pilot).

To Grandad Flyer and 10W - the idea of putting normal or expected levels on charts is a good one which is being progressed where appropriate. However, there are so many of these levels that there must be a limit as to how many can be introduced before the charts become virtually unreadable. There is also the risk that some pilots will read the expected level as a requirement and descend without clearance. We must also cater for the average American aircrew who seem incapable of reading/listening/understanding the simplest ATC instruction or chart - that's not xenophobia, just bitter experience over many years.

N-N

[dessert-rat]

Another factor to condsider is the possibility of a frequency change between restrictions, and where the previous sector still has the requirement for one reason or another.

At the end of the day, when in doubt, ask ( I know you "busy sectors" hate that statement, but it's true)

[Bern Oulli]

Surely the fact that Hooperfly had to ask the question in the first place is evidence enough that the two instructions are potentially confusing - therefore de-conflict them, assuming you knew what the other guy had said in the first place! Now I'm confused.

Disregard my next instruction.