Training programs are a lot different throughout the world. In the US for example, you could study at a university (e.g. Embry Riddle), elsewhere it is a training program with the ANSP.
I enjoyed a high-quality training by the only German provider called "Deutsche Flugsicherung". The selection procress has four stages:
Once having succesfully completed the application process, I was invited to the DFS academy, near frankfurt airport. We used to live in a dormatory on campus which is sadly history now, but the classes still take place at the same building. Depending on the demand of trainees, you will take one of the following training programs:
I was in a lower area control center and approach class. In the first six of eighteen months at the academy, we got to know all the basics of aviation. A lot of theory classes with exams at the end of each module. We had to learn about Air Traffic Management, Law, Meteorology, National Legislation, Radio Telephony Communication, Aircraft, English, Equipment and some more subjects. The first simulator sessions were very basic: How can an aircraft be identified? What methods of seperation can we use? How do we recognize and solve conflicts?
The next step was the so-called "Rating A" - still some theory classes but mainly radar simulation. With a rising amount and complexity of air traffic, it started to become very challenging. Every run of 30 minutes up to 2 hours was rated by a personal coach. We also got a glimpse into working tower, having a 2-week tower simulator class (see picture on the left; 3D-Tower-Sim).
"Rating B" is the last stage of simulation, with very high traffic density and complex conflicts. Every solution found, may cause another problem. Emergency procedures also took part in simulation here. Before completing the training at the academy, there is a week of examinations at the very end. I had to do the approach sector (similar to Frankfurt Approach), and two center sectors - one as executive controller, the other as coordinator. When this last exam is done, the trainees get relocated to the facilities. Some of us went to the ACC Langen, some to Bremen, where I continued training "on-the-job".
After only a very short break, we found ourselves back in the theory class. Before getting into live air traffic, we had to familiarize with our new working environment. The systems we use are a
bit different compared to the simulator we used at the academy. Furthermore, we got to know our new sectors. There are a lot of details to learn and understand, such as sector boundaries,
frequencies of neighbour-sectors, procedures for departures and arrivals and transfer-conditions to the next sector...
Three months of theory and some simulatior-sessions later, we finally had our first day controlling real aircraft. I still remember my first ATC-clearence ever given - it was an Airbus 320 from Stuttgart to Berlin:
"Air Berlin 460U turn right heading 050, cleared ILS approach runway 08 left".
That was a great day! While training on-the-job, trainees have their own coaches sitting behind all the time. In the first stage, they help a lot and give instructions. The longer you work on the sector, the more will the coaches let their trainees create their own style of working air traffic. On every sector, there is a theoretical and a practical exam. In Bremen, we have 4 sectors in a sector group, which we have to complete until we are done with the training. In total it lasts about 3,5 years from the first day at the academy until being checked out on all sectors.