The 'Root Cause' of this tragic accident is very simple. The authority of the Captain was compromised.
Many moons ago, I was a Flight Lieutenant passenger in an Army Air Corps Sioux helo. The pilot was a Corporal in the Catering Corps. Naturally, I deferred to him as the Captain of the aircraft.
A while later, as the Flight Lieutenant Captain of a Nimrod, we had our AOC on board. Yes, he who signed all our Flying Orders. He was a Navigator, so started the trip at the Nav station. Later in the sortie, on intercom, so the whole crew heard him, he asked my permission to visit the flight deck, thereby acknowledging that a junior officer Captain was in command. A memorable moment for all present; CRM in spades.