Peter wrote:
An ATZ in Class G is an area within which ATC has some level of authority over airborne traffic even though it is OCAS. It is the quid pro quo for having Class G everywhere. The unsavoury aspects of recent events are to do with misapplication of the process, especially when the “tower” is not ATC.
Obviously the first question that raises is what “some level of authority” means, and why there is a controller who isn’t a controller.
This extra ATZ, CTR, RMZ etc stuff is still completely wacko IMHO 
gallois wrote:
Wouldn’t it be good if instead of an ATZ, a pilot wishing to transit a sensible area around an airfield could call up the ATS on that airfield and not get “standby” unless there are obviously others talking on the frequency, and transit or integration given quickly and efficiently. Eg “We have 4 in the circuit and 1 overhead 2000’, suggest 1500ft and pass directly overhead the threshold, report crossing runway axis” The rest is down to see and avoid. Oh yes, isn’t that what happens in the U.S.A.
Its not exactly what happens in the US because unless the airport is in Class D or higher airspace, there is no “ATS” by definition, unless somebody were talking to en route ATC in Class E before descending (??). You just do it, and announce on frequency. I was doing something similar today, practicing run and break approaches at a uncontrolled airport. After each T&G I’d leave the traffic pattern from the crosswind leg, fly a big 270 degree arc around the airport to position myself for a two mile initial (extended final) at traffic pattern altitude, then do the break from roughly cruise speed, a fairly tight circling approach to another T&G, then repeat. Meanwhile the aerobatic box on the other (dead) side was active from ground level to 6000 ft or something (I don’t actually know) and when each aerobatic plane finished its practice session it’d cross the runway centerline at mid field descending into the downwind in some self selected way and do its own tight circling approach to land. Nobody the whole time I was there made a standard pattern, but since it wasn’t too busy it worked fine with a few self announcements on Common Traffic Advisory Frequency, 122.8 for this airport. If it’s busy everybody tightens up and flies normal patterns instead, leaves to find somewhere quieter or if transiting the area gives the place a wider berth, as appropriate.
The nice lady in the office today did tell me the ‘box’ was active as I self announced inbound. She’s a local government employee who runs three airports herself, solo, no other staff on site and she’s only at one at a time. She wouldn’t give specific traffic information or advice. I was initially confused by a plane circling randomly (or so it appeared) on the ‘wrong’ side of the airport, visible to me on ADS-B but apparently not on frequency. I think he was concentrating on flying his sequence, probably on some other frequency and talking to an instructor on the ground with a handheld while in the ‘box’
Silvaire wrote:
This extra ATZ, CTR, RMZ etc stuff is still completely wacko IMHO
In the US, how do you know if an airport in Class G airspace has an operational control tower? Is it marked on the chart?
I saw the following in the Code of Federal Regulations:
§ 91.126 Operating on or in the vicinity of an airport in Class G airspace.
….
(d) Communications with control towers. Unless otherwise authorized or required by ATC, no person may operate an aircraft to, from, through, or on an airport having an operational control tower unless two-way radio communications are maintained between that aircraft and the control tower. Communications must be established prior to 4 nautical miles from the airport, up to and including 2,500 feet AGL….
Reference: https://ecfr.federalregister.gov/current/title-14/chapter-I/subchapter-F/part-91#p-91.126(d)
derek wrote:
In the US, how do you know if an airport in Class G airspace has an operational control tower? Is it marked on the chart?
Every US airport with a tower is surrounded by Class D or higher airspace. Maybe there’s an exception somewhere, but not that I’ve ever seen.
US airspace shorthand follows, minus weather considerations. Close enough to keep you out of trouble:
Class D = tower controlled small airport and nothing else. The ‘control zone’ is one and the same as the Class D airspace and it goes to the ground. You need radio contact with the tower to enter during hours of tower operation. If the tower is closed at night the Class D becomes Class E
Class C = bigger airport generally requiring contact with approach and then being handed off to the tower versus cold calling. More complex construction than at Class D airports and as with them you need radio contact to enter. Only a few per state.
Class B = big chunks of airspace around large commercial and military airports, goes up to 10,000 ft. Basically the same procedure as Class C except you need an explicit ATC clearance to enter. Wedding cake construction, roughly, so mostly you can fly under and never talk to them even when your destination is another local Class D or uncontrolled airport. The Mode C plus ADS-B OUT requirement is associated only with Class B and is a simple 30 nm radius circle to the ground but if you’ve got those and are VFR, you don’t think about it or need to squawk anything special. Only a few Class B airports per state, some states have none.
Class A = doesn’t exist below 18,000 ft.
Everything else is Class E or G which requires no contact with ATC anywhere, including at airports. All airspace between 10,000 and 18,000 ft is Class E. Any airport outside of Class D or higher airspace is uncontrolled with no ATC ground personnel.
That’s all you need to know.
Silvaire wrote:
Every US airport with a tower is surrounded by Class D or higher airspace. Maybe there’s an exception somewhere, but not that I’ve ever seen.
Thanks. That is a very nice summary and more or less how I thought it worked, which is why I was a bit confused by the stuff I quoted in the regs.
Silvaire wrote:
Every US airport with a tower is surrounded by Class D or higher airspace. Maybe there’s an exception somewhere, but not that I’ve ever seen.
There are airports with control towers without class D in the US, they aren’t common, but they do exist. Indeed on my checkride I had to overfly one – KSGR, which at the time didn’t have class D airspace. (It does have a class D now. It used to be a contract (non-FAA) tower, and the controllers there had a ‘reputation’…)
On US charts, non-towered airports are magenta and towered airports are blue, so they are very easy to tell apart.
