First of all, the chopper had no business flying in those weather conditions. It was way too foggy and consequently visibility was extremely low. Yet the pilot was extremely experienced and had been flying for years. He also maintained radio contact almost the entire time until the very end. Also a lot of experts are saying his last maneuver was inexplicable. He rapidly decelerated and then accelerated which is abnormal.

I guess accidents can happen to anyone even if you know what you're doing.