Have to think on this one…about 6 months…
After 9+ years in the Air force I decided to get out an do the same thing for the FAA.
Held the same certificates, same rules, using same procedures, etc. They didn’t care. Must start from scratch.
Ok, fine, I’ll do it. Prior to taking “The Test” I watched a few of my co-workers try the same thing, fail, and end up right back amongst us. Made me think.
Took the test anyway along with a couple others from my ‘shop’.
One of those timed tests where you have no clue how you did walking out of the room later. Of the three of us somehow I got the highest score. But, due to ‘quotas’ (this was mid 1980’s) I was hired last.
So I spent 6-ish months on my mom’s back porch with a stack of books, rules & regs, maps, charts, etc and set about memorizing it all and trying to teach myself what I imagined the screening process would want me to know. That part didnt help - the ‘school’ didn’t like broadcasting the 'how to’s" to the public. And this was long before the Internet. May be different now. Oh, and fishing 
Made it thru the academy as a the honor grad for my region, which was a long ways away from home. I mention this cos I was interviewed after by some of the staff about it.
They wondered why I scored so much higher than those from that region (near the academy). “Well I’m Joe Average, I just worked harder I think, I watched them all go home and party on the weekends…I didn’t have that option…”. Made sense to me. And my Bondo-Buggy car barely made there in the first place (made an average of $9,350 A YEAR in the Air Force then).
Prior to that however, The “You made it” final cut announcement was cruel: they called all 24 of us (from our region) into a classroom and said, “If your name is called, 'move on to the other room, the rest of you stay here”. That’s all they said.
Naturally we’re all thinking, 'boy, hope my name’s on the ‘move on…’ list" - the impression they gave us was: if your name is called you passed.
Finally it got down to where only 6 of us were left [in the original classroom]. No way, can’t be! My heart was sinking; 9 years + 6 months riding the porch + 5 months of this screening process - NO!. Then the instructor lead said, "Congratulations, you [6] passed’. Whew! Wasn’t funny.
Another 3 years of training then set loose on the unsuspecting public.
24 years til my next break, but that one doesn’t count.