With regard to rolling too low, let us not forget the T-34C Mentor at Mildenhall in the 80’s, first fatal crash I witnessed and not dealt with very sensitively by the authorities either, having been shocked by the incident, it didn’t help to witness the poor victims being recovered and zipped into their body bags right in front of thousands of spectators, a scene I’ll never forget.
Too low following IIRC a stall turn. A/C impacted quite close to some parked KC135s. Pilot had been requested by ATC to “fill in” for a few moments and thus introduced the “only fly your practiced sequence rules” for display flying – no more, no less.. There is a video of the incident on youtube. Being a small aircraft and there being no expolosion, I’m sure many in the crowd had no idea what had happened.
I too have witnessed a number of air show accidents (too many), including this crash, but I seem to remember it performing a loop (too low) and impacting at the bottom of it. As Kodak mentions, I don’t think many people realised what had happened, including the commentator.
I was there with a friend right in front of this impact and I was that annoyed at no help (in the guise of emergency services, as Pete Truman mentions) coming that he had to restrain me, as all I wanted to do was go and help, they took a hell of a time getting there.
I’m sure I have photos just before and just after the impact, as I was just shooting him through the loop.