So let’s take a look at this as if we are departing a Class C or D airport.
The first thing we’ll do is get the ATIS (which is recorded every hour, or as needed by the Ground Controller)
Once we have the ATIS, then we’ll go ahead and get our Clearance from Clearance Delivery.
Often times at not busy airports it is the same person working ground and clearance delivery. We’ll call clearance and give them the “information” and request to pick up our IFR clearance (it is usually different slightly from what you filed). After you file your route with FSS over the phone or electronically from the computer or iPad, the ATC computer will see where you want to go and make a determination on the best way for you to get there. It takes a few minutes for this to process, so it’s best to wait a few minutes (5-10 minutes) between filing your flight plan and calling clearance to pick it up. Once you have your clearance, the Clearance Delivery controller passes your information off to the Ground Controller and they’ll be expecting you to call for taxi soon (like we said before, Ground and Clearance Delivery is often the same person).
Now at really busy airports, you’ll see a “metering” frequency. If you ever see a “metering” frequency on your airport diagram or the chart supplement, you’ll call them first and tell them where you are and that you’re ready for taxi. Metering then has ground CALL YOU, rather than you call them. This reduces congestion in airports, like Chicago and New York. 99% of the time though, for the type of flying you are likely to do, you will just call ground directly when you are ready to taxi.
Remember the ground controller can get pretty busy, recording a new ATIS, reading someone a Clearance on the other frequency, etc. If they don’t get back to you right away, give them a little time and then try again. Ground and Tower work together up in the tower “cab” or the very top of the tower. This way they can communicate easily with each other and visually look outside the window to see you.