Comment by rob74

That's actually the crux of the matter - not only shouldn't they have done training (at night, with night vision goggles) in conditions where aircraft could be only 30 m apart, this construct of a helicopter flight corridor being within an altimeter's tolerance of the glide path for an airport runway shouldn't have been allowed to happen at all! It's unfortunate that the article focuses on who made what missteps and doesn't mention this systemic issue.