I have to say that in 40 years in the RAF I can recall only one accident in the Loop which, if I remember correctly (and it is from memory) was a Hawk in the 1980s. There have been loads of near misses the most recent of which was a Typhoon that missed Corris Corner. Not too long ago, whilst I was working at RAF Valley (as a civilian instructor/lecturer) there was a Hawk that almost conflicted with a Tornado formation, avoided by an alert instructor in the Hawk and I also recall a very white faced student climbing out of a Hawk having just had a very close inspection of a Sea King in the Ogwen Valley. There have been several fatal incidents in the Scottish highlands the most notable of which was probably a C130 that turned into the wrong valley - a blind valley.
I do love the Ospreys in the Loop and the C17’s are quite impressive too. My favourite video was, I think, a Canadian F16 through Corris Corner, below the level of the hilltop, looking up through the top of the canopy and waving at the cameras.
All of the fast jets through there do get very low, F15’s included, but you can usually tell the newbies as they do take a couple of circuits to learn the topography 