Assign Cruising Level

[singalong]

What are the principles?

Leading Aircraft A flight plan FL340, when its passing around FL280 it asks for FL360. Succeeding Aircraft B flight plan FL360, but not on frequency yet. Would you swap their levels? (Aircraft B doesn't know its cruising level and not yet assigned FL360).
In this instance, I believe should be first come first served and leading aircraft should have priority.
How does your part of the world work?

[5milesbaby]

There are far too many variables to give any straight answer.

Basically I would go first come first served however you have only filed FL340 and there are occasions where I would consider that and not climb you above FL340. If you want higher, file it. As we now have lots of flow control and vertical sector splits then you could be flowed in a lower sector and, by climbing to FL360, climb above the lower sector and fly through a higher one for which you have no slot. Its easy for us to work out what happens to that effect on short flights but as soon as you cross into another FIR then it all starts becoming unknown hence nothing climbing above filed levels. Other traffic can also become a factor be it slower in front or faster behind, and if your routes diverge or not in the near future. As I said, far too many varibles.....

[finallyflying]

To answer your question on a simple basis (in a pleasant world away from flow control and high-level sector splits :)) the answer is Yes, the leading aircraft should have priority.

ICAO (pretty sure its in 4444) says Aircraft AT the level has priority, not aircraft filing the level. If the 360 man is behind you and already at the level, and in conflict, then of course, no, you won't get it. But the level on a Filed flight plan is about as inaccurate as the filed speed, and we know that; mostly it sits on an RPL (Repetitive Flight Plan) registered a few years ago!

[singalong]

Exactly. Thank you Finallyflying.

5milesbaby, no other factors play a part in this scenario. Nothing prohibits the leading aircraft from having FL360.

[radarbloke.ana]

Totally agree with FF. :ok:

[5milesbaby]

Singalong, interesting one then for you happened yesterday.

Lead aircraft A340-300 filed FL340 requesting FL320 called on frequency abeam point A passing FL220 climbing at about 800ft/min with a groundspeed of around 380kts. Following aircraft B777-300ER was 11 miles behind and called on frequency about a minute later (as it also was abeam point A) passing FL250 (already 1500ft higher than lead aircraft) climbing with rate 2200ft/min filed FL370 requesting FL320 with a groundspeed of 425kts increasing all the time. The following aircraft was climbed to FL320 and the first aircraft given FL300. The B777 leveled about 25 miles after point A and the A340 about 45 miles after point A at which point they were only 3 miles in trail with the A340 in front. They stayed like that for over 100 miles and I would expect much further as they had filed the same route to the same oceanic entry point.

Hope that example shows that its not always first come first served in longitudinal senses, if you get to the level first then that can alter allocations.

[Waterfall]

But probably thats exactly what finallyflying said about conflicts with the ACFT behind-if there is one already at the level or has already been assigned-the leading aircraft wont get it.

[divingduck]

the decision is made by whatever is the easiest for me:E

[Arkady]

I'd say the 777 was always going to get the higher level, whether it was above or below the A340 on first call, on the basis that it would reach FL320 first. Or as Divingduck put it "the decision is made by whatever is the easiest for me" :D

[shamrock]

Jaysus, that's more information than I could handle in a whole shift !

Now that I've read it six times, makes sense . As the triple is already above the A340 and also behind and faster, then its a hell of a lot easier for ATC to assign FL320 to him.

Otherwise, with the A340 climbing slower than a wet wednesday, the 777 is going to have to be vectored around him, and this sounds like a Brecon-Strumble example with not a lot of room on the airway.

And in essence, that's why he gets it. If the 777 was under him, most controllers would slap on a rate of climb restriction and level him at 300.

I guess the exception proves the rule.

[ferris]

Grey area.
ICAO says 'first to use the airspace', but also says that a controller may alter that if significant economic benefit would flow to multiple a/c.
I guess it could/should be argued that if ATM rules are creeping in saying "flight planned level only" etc. then that is, by it's very existence, creating sig econ benefit (airspace capacity).

And yeah, agree wholeheartedly with DD.

[pdcta]

FILE IT, FLY IT!
Sorry but this is my point of view. Capacity in some sectors is close to 50 acft/hr and often the flight demand is above 70 per hour during peak hours. Even under regulation happened that we experienced in overdelivery problems due to wrong assignment of the requested/filed cruising flight level.


Have a look on:

EUROCONTROL - Flight Plan & ATFCM adherence (http://www.eurocontrol.int/dmean/public/standard_page/FPL_ATFCM_adherence.html)

http://www.eurocontrol.int/dmean/gallery/content/public/Library/Adherence_brochure_Apr09.pdf

[Knackers]

the decision is made by whatever is the easiest for me

We must have had the same instructors:)

[30W]

FILE IT, FLY IT!

pdcta,

From a pilots point of view that's not always possible:-

1. The AO files the plan and requested level several hours ahead of STD. This is based on computer predictions of planned weights and minimum fuel loadings.

2. The above calculations are just that - 'Predictions' - the actual aircraft weight at departure can preclude climb straight to FPL as it's easier to be heavier, and therefore not capable. Payload prediction can change. Additional fuel carried over and above legal minima can occur on many occasions because the crew have valid reasons for loading more.

3. The tactical situation I.M.H.O is far more variable than your 'stick rigidly to everything in the filed FPL' sentiment suggests:- CTOT's mean being airborne within a 15 minute window of the FPL time, so the ACTUAL presentation and appearance of traffic to a sector is still VERY variable, based on just initial FPL data. This HAS to effect the decision making process that an individual controller HAS to make to allow safe and efficient controlling.

4. I very much appreciate sectorisation, and capacity issues that occur when at different to FPL. I couldn't possibly count the times I have been filed and flown at say FL340, then been asked if I could accept FL360. Having accepted, because it HELPS the resolution of a problem for the controller concerned, I have then been transferred at new FL continually en-route at that higher level, including into airspace we have tactically filed under at FL340 in the first place for capacity issues.

What I do believe is that ATC must be left to BEST manage the tactical picture at the time. Pilots should NOT abuse capacity planning by REQUESTING levels that would infringe tactical level planning to avoid CFMU restriction.

Brgds
30W

[divingduck]

Pilots should NOT abuse capacity planning by REQUESTING levels that would infringe tactical level planning to avoid CFMU restriction.

Hey 30W...you obviously don't fly for Ryanair then.....:ugh:

[thealps]

Interesting subject since we're constantly discussing this subject at our centre. Having 6 vertically split "upper-sectors" (FL 250+) it has a huge impact on the traffic load (in certain sectors) if a lot of A/C don't fly their filed levels.

However, me and most atco:s here try to fulfil most requests of higher levels. It then, sometimes, shoots back at us when certain centres further down the road complain that we send too many a/c on the "wrong" levels.
I personally think that, most of the time, the number of a/c flying at higher levels than filed equals the "high-filers" not capable of climbing to filed cruising level.

The biggest problem for us is that in a sector with only 2 or 3 flightlevels, and where every a/c is a potential conflict with the others, having 10 more a/c per hour than sector capacity makes a huge difference!

It should be said that a number of atco:s never climb a/c higher than filed level, no matter what. They're not many but there are a few. Guess they want to keep their back clear.

It's a subject that will continue to be discussed for sure.