Airborne_Again wrote:
In Sweden you may only fly in an ATZ in connection with take off or landing. None of these rules are covered by airspace classes. Sure, the Swedish ATZ rule could be replaced by a restricted area with the same flight restriction, but I’m not sure that would improve things.
But why would you like to create such a restriction (or any other of the special rules mentioned above) at all? The US has a fairly simple system, with a lower number of exceptions than about any single European country and it surely can handle SEPs and widebody airliners flying from the very same runway. In fact, probably it is the best system in the world in this aspect.
I suspect the ATZ tends to be a relic from the days when a lot of the controlled airspace was only what we would now classify as E. I learned to fly in Essex in 1986, and I seem to remember that an ATZ was all Stansted (and it was “Stansted”, not “London Stansted”!) had at the time. Most of the bigger airports then got wrapped in “special rules airspace”. So the airspace gets built up where there’s traffic load, but there’s no incentive to disestablish the good old ATZ. I do remember the decision to stop depicting the ATZs of the main class D airport, probably 10-15 years ago.
Silvaire wrote:
I don’t think additional rules need to exist.
I agree. You can always find “good” reasons for a special rule. It’s just that when you add all these peculiarities up, you get confusion and disorder. It ends up as friction in the system.
In the US, class D is generally used where we would expect an ATZ, for instance at David Wayne Hooks:
https://skyvector.com/?ll=30.062342814662134,-95.5405266479211&chart=111&zoom=3
But sometimes towered airfields in the US don’t even have that. For example KTME:
https://skyvector.com/?ll=29.817026257318258,-95.89389249340825&chart=111&zoom=3
…although this is rare, and in the case of KTME they are getting a class D.
Silvaire wrote:
It’s authorized by the tower within the Class D etc. surrounding the airport.
So that’s a “control zone”. It’s just that it has a name in Europe (and by ICAO!), while in the US it is called the class X “surrounding the airport”.
I don’t think additional rules need to exist.
They do because the ATZ is in class G.
Airborne_Again wrote:
They do because the ATZ is in class G.
We have no ATZs in Norway that I know of, not since I got my PPL in 92. They are all CTR in C/D or TIZ in G when towered. Nothing when un-towered in G. The CTR/TIZ is a volume of air surrounding an airport where the tower is in “charge” with a separate frequency usually and perhaps a separate radar. Surrounding is a TMA or TIA with another frequency (usually). There could be pockets of TIZs (AFISes in G) within a TMA (C/D) also, but there is also vertical separation, the TMA/TIA never extends down to ground as CTR and TIZ do.
As far as I can see, ATZ is not very well defined. Is it controlled or uncontrolled? Whereas TIZ and CTR are well defined. In G, why would you have a ATZ instead of TIZ? and in C/D why a ATZ instead of CTR?
LeSving wrote:
We have no ATZs in Norway that I know of, not since I got my PPL in 92.There are very few of them in Sweden – two or three. They are established around airports where — given the general traffic situation — you could expect a lot of overflights at low level so the ATZs are intended to prevent that. Both that I know of are adjacent to the control zones of controlled airports with lots of VFR traffic. (Well, in one case it used to have a lot of VFR traffic.)
As far as I can see, ATZ is not very well defined.
No, they’re not. IIRC the ICAO SARPS just say that it an airspace defined for the “protection” of the airport.
Silvaire wrote:
My point is obviously that CTA, CTR, ATZs and other redundant airspace definitions serve no useful purpose except to create confusion, as demonstrated by the original post.
Blinkers on?
Peter_Mundy’s post has an example.
I don’t see how the original post has any confusion around the use of the definition CTA/CTR.
Airborne_Again wrote:
So that’s a “control zone”. It’s just that it has a name in Europe (and by ICAO!), while in the US it is called the class X “surrounding the airport”.
Of course, but the point is that there is no need for redundant airspace definitions. Classes A through F is clear, adequate, and simple. Complexity breeds confusion, and provides yet another obstacle to making European flying easy, as it should be. I can only assume this is why getting a pilot’s license in Europe requires eight separate written exams or whatever unbelievable number it is.
When lettered ICAO airspace definitions were rolled out in the US 20-25 years ago, control zones and TCAs and the other old stuff was dropped. Most ATC controlled airports were given Class D airspace to replace their control zone and the terminology got simpler, it didn’t add another layer and get more complex.
Airborne_Again wrote:
They do because the ATZ is in class G.
I think that’s another airspace concept that doesn’t need to exist. In the US there are standard procedures for operating around non-tower fields in Classes E or below. There is no need for special, poorly defined airspace assigned on an individual basis, or for that matter having people on the ground who may or may not have some level of authority (who knows? 
) to sort of direct traffic at a non-tower airport in Class E, F or G airspace. The same goes for towered airports in Class D airspace outside of tower hours of operation, which can simply assume standard non-tower airport procedures.
Silvaire wrote:
Classes A through F is clear, adequate, and simple. Complexity breeds confusion, and provides yet another obstacle to making European flying easy, as it should be.
Yes, but I don’t see how a CTR makes things more complex. A CTR is defined as a controlled airspace going from the ground and up to a specific alt, around an airport. Airspace classes have no such definition, they don’t specify anything like this, and they don’t mark any borders for frequencies and communication. Below are two examples, one with a TMA and one with a TIA. From the ground and up to the TMA/TIA the airspace is G. The TMA is C and the TIA is G with RMZ (two way radio is required due to IFR airfields). Below the TIA/TMA you can fly freely, but you cannot enter CTR without clearance and TIZ without two way radio. In the TMA/TIA you communicate on one single frequency, and can fly “freely” as long a it is above the CTR/TIZ (In C you obviously need clearance but not in G (TIA)).
Without the CTR, you would need to use a different airspace than the TMA, or it would be the same thing. You could have D exclusively for airfields for instance and C/G elsewhere, but that wouldn’t make it simpler, and what about the TIZ that is in G?
