Comment by stackskipton

The thing I keep looking for is dropout/failure rate. If their change in hiring procedure resulted in higher dropout/failure rate, then yes, this impacting ATC staffing but it would have been slow burn.

ATC staffing is bottlenecked by the training dropout/failure rate. 1000 people a year go in, pretty sizable dropout or fail so you are left with 500. If 700 are retiring, that's -200 overall. At some point, that -200 year over year becomes impactful.

So, if you need more people, you have two options. Increase the class size but obviously that's expensive and makes the problem slightly worse up front as you are pulling qualified people into instructor roles.

Or try to filter out those who will drop/fail in hiring process so they don't occupy class slots. One of the ways FAA had done that is CTI college courses because those graduates had lower drop/fail rate.