Hi,
Reading the prelimary report, I could think about a few possibilities, that could lead to a non significant NR.
I.E. an overspeed on one engine. You than need to pull the collective underneath your armpit, to keep NR on the clock.
Killing that engine, i.e. with fuel cut (firebutton) will result in a massive decay of NR, if you don't drop the collective rapidly, cause the remaining engine just can"t spool up that quick from 0TQ to 120% or so, which would be needed, to save the NR with a high pitch setting.
Seen it at the simulator - and was busy, even with the Copilot killing the engine on a countdown...
That in mind, I'm back to the operators decission, to excecute night ops single pilot....
Yes, there heros outside, who can handle all and even can transmit a MayDayCall - but thats the old breed of pilots, which were choosen by the military, cause their character has a part - overconfidence...
Which is good, if you want to send the guys in dangerous - lethal - situations, but isn't, what you want for normal commercial operations.
Big operators payed for surveys, cause that's cheaper than an accident and if you're clever, you look, what they have found to human capabilities under stress.
For the heros- continue as before
For the others, who want to survive and enjoy their pensions - aviate, navigate, communicate...
What can help you in case of - and doesn't distract to much from aviating - Switch the ELT on - it doesn't always go of after a crash - so if there is only little or no time for a MayDayCall, this may save your butt - if you know, where the switch is - and you don't have to search for it....
With amount of the fuel found in the helicopter engine starvation doesn´t seem to be the cause.