An INOP A/P should be marked as such, and the relevant circuit breaker should be pulled with a ring placed on it so it can’t be re set.
I’ve got a “modern” AP connected to my GRT EFIS and it’s very good. It flies far better than I can. I’ve heard the same from the guys with Garmin and Dynon.
Mine is the first aircraft I’ve flown with a working AP, even in CH. On every checkout in the last 40+ years w/aircraft that had an AP, the instructor said “don’t touch it – it will kill you” – as said by others, perhaps because they didn’t take the time to learn it, or simply didn’t want to take the time to teach it to me in case it did cause a problem.
Out of eight school/club aircraft I’ve flown at EGTR (Elstree), only one had operational autopilot (two-axis).
