what next,
"Add commercial pressures and high workload to that. His decision was certainly a big mistake. But criminal?"
If the driver of a coach went over the centre line of a motorway, and because of that action people were killed or injured, would you say that action was a "big mistake" or criminal negligence?. If yes, for criminal negligence which would very likely be the end result, then why the difference? because one is driving an aeroplane and one a coach??