Ahhh, well I think it falls into two camps. Those that believe an accident is avoidable and those that think it's unavoidable.
I am in the avoidable camp. You may not intend to lose control and kill the family but why did you lose control? Were you going too fast (avoidable), conditions bad (see last one - two fast for the conditions can be 15 mph....), car badly maintained (avoidable), 'it came of nowhere!!!!' (Did it hell, you didn't notice it - avoidable), etc etc.
Ok, nobody intended it to happen but usually it's avoidable. To me that would make it a crash. The person driving the car has intentionally made an input - steering, throttle, brake etc.
Another car example..... You are on a track day and you've done a few laps, you are in the zone but you feel the brake travel a little more than usual. You continue to push on. Three corners time you wipe out two cars. Is that a really unfortunate accident? Or should you have started a cool down and pitted while your brakes recover? You certainly didn't intend to wipe out the two cars but you did. Accident or crash?
Maybe my thoughts are if there is accountability then it's not an accident.
As I say, it's a debate,