Baro altitude. That is the definition of the airspace.
Airspace is much worse in parts of France – practically impossible to decipher in the Nice area. France also mixes altitude and FL all over the place. But France has a much better ATS.
Peter wrote:
I wouldn’t mind to pay it for the SEPs I usually fly at the Eurocontrol charges-levelYou would be alone. The route charges are of the order of 50/hr.
It is actually more like 30/hr. And just add 15% to the cost of the flight in PA28.
In some cases I would actually like to do it that way (if I’m actually getting the service!) and I know of others that would too, but, again, there is no option.
The problem right now is that even if you paying for the service (for example, flying 2T+ a/c), you are OCAS on the right frequency, you can still bust CAS – ATC won’t tell you!
Alpha_Floor wrote:
They just can’t be used by aircraft in flight but they sure as hell can and do define the limits of airspace.
How can your aircraft be at a flight level that cannot be used and bust the CAS? I admit I should have said “as if” it doesn’t exist and made it clearer. But I used my wording for the dramatic effect to better explain the point. Which is that we fly according to a system and this system is explained in your AIP as linked by me in your quote and according to that system you are either at or below the TA or you are in flight levels. So if you are flying at the TA, by the definition of the rules and system we use, you cannot be in the flight levels.
The airspace boundary of course does not change. So in the scenario where the TA is 4500’ and FL55 is the lower limit, and we have a severe low pressure, you would bust this lower limit if you climb above the TA. At or below the TA you cannot bust FL55, as you are in altitudes. So 4500’ is fine, 4501’ you technically are suppose to change to QNE in your altimeter and the altitude reading it would give you would instantly put you above FL55 busting the CAS. Since your CAA seems to take busts very seriously, as indicated by the fact that in your AIP they strongly advise to keep a buffer of 200’ or even 500’ I wouldn’t recommend actually flying at the TA in our scenario. But technically if you could maintain your altitude perfectly, 4500’, even if there is a severe low pressure, is not and cannot ever be a bust of a boundary of FL55.
Bottom line, just read the damn rules: https://nats-uk.ead-it.com/cms-nats/opencms/en/Publications/AIP/Current-AIRAC/html/eAIP/EG-ENR-1.7-en-GB.html#ENR-1.7
They even give you the exact scenarios and what the correct procedure is!
hazek wrote:
How can your aircraft be at a flight level that cannot be used and bust the CAS?
An aircraft in flight is always at “A” flight level and also at the same time at “A” altitude w.r.t. a given iso-pressure surface and also at “A” given height w.r.t. some datum or reference. What don’t you understand about this?
hazek wrote:
So if you are flying at the TA, by the definition of the rules and system we use, you cannot be in the flight levels.
You don’t understand what a flight level is. The existence or definition of a flight level has NOTHING to do with TA/TL. I gave you the definition of flight level. Edit: No I didn’t, so I add it here: flight level = surface of constant atmospheric pressure which is vertically offset from the QNE pressure surface datum/reference by a distance expressed in hundreds of feet.
Flight levels don’t cease to exist below the TA. They generally aren’t “USED” by aircraft in flight but they still “EXIST”.
Just look at any altitude-related weather chart: they depict wx at FL000, FL020, FL050 even in areas where the TA is much higher than that.
hazek wrote:
So in the scenario where the TA is 4500’ and FL55 is the lower limit, and we have a severe low pressure, you would bust this lower limit if you climb above the TA. At or below the TA you cannot bust FL55, as you are in altitudes. So 4500’ is fine
Go and do this under the London TMA and then tell me what happens with your licence…
hazek wrote:
So in the scenario where the TA is 4500’ and FL55 is the lower limit, and we have a severe low pressure, you would bust this lower limit if you climb above the TA. At or below the TA you cannot bust FL55, as you are in altitudes. So 4500’ is fine, 4501’ you technically are suppose to change to QNE in your altimeter and the altitude reading it would give you would instantly put you above FL55 busting the CAS.
That does make sense, however….
Bottom line, just read the damn rules: https://nats-uk.ead-it.com/cms-nats/opencms/en/Publications/AIP/Current-AIRAC/html/eAIP/EG-ENR-1.7-en-GB.html#ENR-1.7
…AIP UK ENR 1.7 actually does not say so – it is your interpretation.
By the way, it is interesting that at the end of ENR 1.7, there is a “Flight level graph” which mentions FL10, which according to you doesn’t exist. (The TA can’t be less than 3000 ft and you would need a QNH of about 1087 to make it FL10 “appear” above 3000 ft.) So if FL10 doesn’t exist, why has the CAA included it in the graph?
How can your aircraft be at FL55 and bust the CAS, if FL55 on that given day cannot be flown?
What aren’t you getting? You have the answer, you said FL55 on that day couldn’t be used but yet somehow you still insist that you can fly it and thereby bust the CAS. How? It’s not possible. You are either to report your position of your aircraft in the altitudes at or below the TA or in FL above. I mean maybe it’s me because I’m not a native speaker of English?
It’s an agreed system of how we determine and aircraft position. Aircraft’s position is what determines if you are in an airspace or not. If we follow the published procedures for reporting the aircraft position in terms of flight level flown, it can only ever be in altitudes or in FLs. It’ cannot be both because that is not how the system is setup. Again, just read here: https://nats-uk.ead-it.com/cms-nats/opencms/en/Publications/AIP/Current-AIRAC/html/eAIP/EG-ENR-1.7-en-GB.html#ENR-1.7
hazek wrote:
How can your aircraft be at FL55 and bust the CAS, if FL55 on that given day cannot be flown?
hazek, keep in mind that even if the TA is 6000ft for the whole solent CTA, it is not going to stop ATC software from generating a “CAS bust” in the system for FL55.
as Alpha_Floor says above – if you disagree, you could fly at that altitude/level on a low pressure day and see what happens to your license.
Well, actually, if you license is not a UK CAA license, then nothing is going to happen, they’ll send a stern letter to your CAA. :)
Airborne_Again wrote:
…AIP UK ENR 1.7 actually does not say so – it is your interpretation.
5.1.4 Within Controlled Airspace a pilot should set one altimeter to the latest Aerodrome QNH prior to take-off. While flying at, or below, the Transition Altitude vertical position will be expressed in terms of altitude based upon the Aerodrome QNH. When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been specifically requested by Air Traffic Control.
5.2.1 Within Controlled Airspace
5.2.1.1 At and above the transition level and during en-route flight the aircraft should be flown at Flight Levels. The latest and most appropriate Regional Pressure Setting value is to be used for checking terrain clearance in flight. Aircraft flying in a Control Zone or TMA at an Altitude at or below the Transition Altitude will be given the appropriate QNH setting in their clearance to enter the Zone/TMA.
Ok, so how do you interpret this then?
This debate – and any possible enforcement – is a great example that the system only works if people apply common sense, and that the attempt to spell everything out in detail is a futile exercise – even the massively bloated EASA rulebook is unable to cover every eventuality.
The written rules (in Europe) are very simple
A pilot flying below the TA has no idea which flight level he is flying, and the system is designed in a way that this works and is safe.
You can now create a theoretical obligation to check you are not vertically infringing an airspace with a floor defined in FL on days with exceptionally low QNH, and start calculating your FL using (remember you only have to have one altimeter), to prevent infringing airspace WHICH ACCORDING TO THE RULES IS EMPTY! Using which value, BTW? Do I now have to carry the ISA tables to get the mb per 1,000 ft which changes from 36mb at 1,000ft to 27.5mb at 10,000ft.
Any sane authority would never pursue a theoretical infringement of empty airspace.
Unfortunately sanity is not something all regulators possess.
arj1 wrote:
hazek, keep in mind that even if the TA is 6000ft for the whole solent CTA, it is not going to stop ATC software from generating a “CAS bust” in the system for FL55.
That would be an incorrect application of the published regulations? I was not arguing whether or not your CAA doesn’t apply the published regulations, only that if the regulations are followed in the mentioned scenario that isn’t a bust. But IF you guys are claiming that your authority doesn’t know how to apply the rules then that’s a different problem and I won’t say anything about it because I don’t know what the situation there is.
But you can be assured that if I ever fly to the UK I would follow the published rules and if questioned defend my actions accordingly.
