Question for US ATC
 

What is the general base (read: most of the continental US) of CTA and what class is it?

Most of the US is Class E above 1200 feet AGL. Around airports with instrument approaches and in cities with lots of radar, Class E above 700 AGL. Occasionally, for some airports, Class E to the ground if there is no tower. Class A starts at 18,000 feet everywhere. Almost no Class G left anywhere, except under the Class E and in a few remote or mountainous spots.

Cool. Thanks. Do you have any approaches to OCTA aerodromes that would be out of surveillance coverage?

There are certainly approaches to airports that have no radar surveillance. Not all Class E has radar coverage. Maybe, after 2020, ADS-B will be used to provide surveillance.

Sweet. What standard would you use for successive arivals or a departure and arrival? I'm thinking there isn't much to use apart from vert/step descent or just one-in/one-out. We have ADSB but some places don't get coverage until FL110, just wondering how you guys deal with non-suveillance approaches from class E and separating traffic.

Arriving traffic contacts ATC when on the ground, or if cancelling IFR. Departing traffic is given a clearance by radio (possibly a remote outlet) or telephone and a "clearance void" time, typically 10 or 15 minutes later. They contact ATC by radio after departure.

Or the flights just go VFR if the weather is suitable.
For example if an aircarft is on approach and is certain to be able to reach it in VFR they often cancel IFR.
Similarly they would depart VFR and pick up their IFR in the air while they are already in radar coverage.
This allows much more throughput depending on the weather.

Ok thanks for the responses. So in IMC you wouldn't have two outside of covereage in and out, you would wait for one to cancel IFR or land?

Correct, the one waits for the IFR release until the inbound either lands and closes the flight plan or cancels IFR while airborne.

GF

Thanks. That's answered it perfectly.

Someone posted this on the Australian forum. Is anyone familiar with this procedure?

If I remember correctly in the USA they will clear IFR aircraft in E to depart in non radar airspace where the first aircraft turns 30 degrees left from runway heading and the next aircraft 30 degrees right . Not initially an ICAO IFR standard but they clearly can’t hit. That is the type of standard we have to copy if we are going to get the NAS to work efficiently without all the delays that are quoted by the ignorant on this site.