A U. S. air-show accident--fatality--but I assume that counts.
I was at the Reading Air Show (Reading, Pennsylvania) in the early summer of 1969 as an editor of Flying Magazine. I thus was outside the crowd barrier, with a photographer's pass. Reading was THE big general aviation show in the U. S. at the time, well before the EAA was anything but a small enthusiast organization.
Not 100 feet in front of me, a Piper J-3 Cub suddenly went in vertically--first aircraft accident I'd ever seen. The pilot was a famous air-show performer, Dick Schramm, who did a classic "crazy flying farmer" act in which he wandered out of the crowd, dressed in bib overalls and a straw hat, and ostensibly sneaked into the cockpit of an idling, parked Cub.
Schramm took off first on one wheel and then the other, cross-controlled every which way, while those people in the crowd who didn't realize it was an act were horrified. After several goofy 50-foot-agl fly-bys, he waved the joystick out the open window as though to say, "What do I do with this?" and as I remember, he dropped it. General consternation.
It was of course a spare stick, and he put into the stick socket in the back seat a second stick he'd hidden away.
Unfortunately, this time he apparently didn't seat the stick properly, and his next maneuver was a very low-altitude loop. On the backside of the loop, coming straight down, the stick popped out of the socket, with the inevitable result. He was of course killed instantly--there wasn't even a fire, just a sound like a watermelon being dropped out of a five-story window--and the sad thing was that the running commentary was being delivered by his son, Dick Schramm Jr., who as I remember was with the Blue Angels as a PA commenter. Schramm Jr. continued with his narration calmly, despite knowing that his father had just died, and warned the crowd to stay back, let emergency personnel handle it, etc. etc.
I've never forgotten that scene.