Level by, clearances?

[nitefiter]

When given a conditional descent clearance,for example descend when ready FL200 and be level 20nm before any waypoint,do you expect the aircraft to exactly hit the 20nm before the waypoint at FL200 or can this be descend and level then maintained at a point before 20nm before the waypoint?
I suppose im asking whats best for you guys in ATC,i always go for the point and accuracy but dont always get it,ive been told off for being "late" and high before but have never been told off for being down a bit early.

[Asda]

A good question. Certainly in the UK a restriction of FL200 20nm before xxx means that you make your descent (or climb if appropriate) to FL200 at any rate you like. We really don't mind how you get there, if you get there early or make a dirty dive at the last moment, but, when it comes to 20nm before xxx we expect you to be level at FL200. There are normally very sensible reasons to actually achieve this level - the FL210 crossing track 5nm after xxx for example - so it is important to let us know if any target level is not achieveable, so we can warm up plan B.

(I'm trying to think of a way to pass an instruction to descend to FL200 20nm before xxx - but not to be level until at least 25nm before xxx - and it all gets horribly complicated and open to confusion and, why would I want to do this anyway? - which is probably why we don't do it)

In short, achieveing the target level early is OK - late, definitely not.

[5milesbaby]

Asda, 2 ways. Either don't clear down for all the descent, or just say be FL210 or above 25nm B4 XXX (or cross Y FL210+). This is very rarely used, but an example is when you are going balls out and have the base of CAS restricting full descent, give a "not below FL until passing" means only one descent clearance and you can get overloaded else where :mad:

Nitefiter - getting down early is fine, if you are given full descent clearance then no conflicts occur,. The reason we give restrictions is to keep you up high as long as you want, but then get you down to the levels we need at certain points.

[Chilli Monster]

As an offshoot - what happens if you can't make it because you're given an impossible descent?

Scenario - overhead BARLU FL340, given "When ready, descend FL200 to be level 10 before KATHY". For those not familiar with Englsh Channel airspace that's a descent of 7000 fpm.

Needless to say we didn't make it!

[LostThePicture]

If the controller is doing his/her job properly, then s/he shouldn't take the piss by asking you to do something only a fighter jock would consider. However, even if the suggestion is completely ludicrous you should say something; preferably along the lines of "Be advised, best level by AAA will be FLxxx", then the sector which has screwed up can coordinate your flight slightly high into the next sector.

LTP

[VectorLine]

Chilli

just curious - what was your destination? and when was this? recently.

Just wondering 'cause I do that bit of airspace

[Carbide Finger]

If you are inbound to Liverpool along UA25 the reason is because Manchester West are going to get you to FL190 10 before MONTY. This is becase the Manchester TMA inbounds are being descended 'on top' of you to be FL200 level 10 before MONTY.

You are transferred to Man W in the descent and they should if able give you a further descent clearance.

If you are going for a late dive for the level and get it wrong it can cause problems.

If you are talking about another standing agreement then just ignore my worthless reply.

CF

[BEXIL160]

errrr....BARLU-KATHY is (U)B11 , not (UA25)...

Can't think why the controller would need you to be level FL200 10 before KATHY. Unless there was an overflight at FL210 routing ORTAC-MID, and the controller needed to get you under him. Radar vectors would normally suffice.

FL200 is used as a level for inbounds to theLOREL2C , and the restriction is to be level 20nm beforeMID (or at AVANT if you prefer.... yes I know AVANT is 18 DME MID, not 20).

This particular sector (S19, or HURN EAST) is an exceptionally complicated and busy piece of airspace. You should notice some changes in the near, and not so near future. One of these will be a requirement for inbounds to EGKK via the WILLO2C to be level at FL300 by FAWBO ( I would have prefered BARLU myself, but nobody asked). There will be other major changes (allegedly)

Back to the thread (or THRED haha)..

Either hit the level restriction on the nail, or be level before. Being level before a restriction is much, much better for ATC. If you are unable to make a restriction (this goes for climbs as well BTW) TELL ATC ASAP and say what you can achieve. This will help him/her enormously.

IDEAL descent profiles (except for CDAs) are soon to be a thing for the past in UK airspace. It's just too busy to give everybody exactly what they want. So start expecting EARLY descents please gentlemen (and ladies). It's really to your advantage as we can accommodate more traffic safely this way, and the alternative is more punitive flow measures.

Best rgds
BEX

[Carbide Finger]

Bexil,

I was just hazarding a guess at the standing agreement nitefiter was refering to, but I completely agree that if you can't make the restriction then tell us!

CF

[5milesbaby]

BEX, aint it FL190 lvl 20 B4 Mid?? But have to agree that being there earlier is good, adn if you cannot get there at all, tell us immediately .

FL200 lvl 10 B4 Kathy can help in certain times such as the LL inbound being just that little further ahead of KK in and telling the KK to be FL200 10 B4 helps the turn at Kathy.

Chilli, understand that in few conditions that its not possible to go from FL340 to FL200 lvl 10 B4, but in most ops there aint a problem. Now if you were still at FL340 at Fawbo......... :uhoh:

[Chilli Monster]

Vector Line - check your PM's

[javelin]

The descents aren't ususally the problem. On the Bus you can easily put conditional height constraints - at or below/at or above in the FMC provided they are put on the plate for initial planning consideration. There are ommissions into LGW and MAN at present. DUB/LON want 290 by LIFFY usually and LON want 270 by GIBSO. They are not on the initial planning box on the appropriate charts and should be as we can modify the descent profile to make the whole affair more efficient.

The big problem is still the climb constraints out of MAN. Most Airbus types that are going a fair distance cannot make 310 - 50 before MID - it just ain't going to happen unless you squander all your energy and then you will have a level acceleration for the next 20 miles. My tack now is to be ready with a best guess at a steady climb speed, say 280kts and when cleared, advise our best possible level. If I need to vector or level, I would rather that than struggle up. A better level would be 280 - that would be achievable nearly all the time.

[055166k]

Any half-decent controller should have a reasonable understanding of your aircraft performance characteristics, but if you are given an unreasonable target then for goodnesss' sake say so.........otherwise some jerk in the training section will tell all the new controllers that you can make it.........and a few years later when those same controllers have left the shopfloor to work in an office you will find that the impossible climb/descent profiles have been written up as procedures in new airspace design models. Talk to the CAA [ not NATS ] via your Chief Pilot if this is a recurring problem.

[javelin]

055166k


Believe me, I have been trying !