[tptacek]

I see interviews with Antoshkin about the lack of precautions taken for the pilots, in stories citing the "600" number as the total number of pilots involved, but nothing establishing 600 fatalities.

I screened the Discovery documentary you're referring to and watched all the segments in which Antoshkin appears. It's the narrator of the special who claims 600 helicopter pilot fatalities, not Antoshkin himself, unless I've missed something. Can the 600 number be squared with the number of helicopters involved (the documentary claims 60, I think) and the number of missions the pilots fly (dozens per day), and with the fact that you can find some of those pilots giving interviews just a few years ago?