My suspicion is, based upon experience of flyers, is that they've both tried to use the same bit of airspace, either as a game of chicken or by sheer accident in poor visibility, despite high tech radar on board........you decide
It is so sad; I've been on search and rescue helos where the pilots love to show off their "skills", so we've flown so low above the waves where we've had the screen wipers on due to wave spray, but that went horribly wrong twice; once when the pilot banked sharply and forgot the length of the rotor arms hence contact was made and we all got very wet and the aircraft was written off. In the second case the waves were so big they created an air vortex above them that robbed the engines of valuable oxygen and they stalled, promptly turning the helo into an eight ton boat! I wouldn't have minded but I was stuck on a cliffside as part of the training and for hours was listed as missing until the rest of the crew were picked up and suddenly remembered where they'd left me!
It is far too early to speculate on the causes of this tragic accident and I pray I'm wrong in my line of thought but there does seem to be a correlation between the skills needed to fly these things and the ability to suddenly have silly thoughts about scaring the aircrew.......!
I hope I'm wrong, I really do!
Sad situation indeed