Arguably, ALL accidents in a technical endeavour are caused by human error.
Indeed. Perhaps I may go a little off-topic and quote a character of Nevil Shute's:
“Accidents don’t just happen of themselves. ... Accidents happen because men are foolish, and reckless, and negligent, and lazy. Sometimes, because there isn’t enough money for what they want to do. One crash in a hundred may have been because God willed it so. Not more than that.”
— An Old Captivity, 1940