This is as expected from the AD:
Investigators found the pilot’s pedals became disconnected from the tail rotor and caused the aircraft to make an uncontrollable right turn before it spun and fell… The pedals and tail rotor are linked by a mechanism which failed after parts of it had become disconnected and there was a “build-up of black grease” on one component. The failure led to the pitch of the tail rotor blades being changed “until they reached the physical limit of their travel”, investigators said.
It could be a tail rotor failure, a tail rotor drive failure or loss of tail rotor effectiveness (LTE). LTE occurs when the rotor is subject to winds that prevent the rotor from carrying-out it’s function; think of something akin to a stall. My money is on a drive failure.
The video shows the helicopter being flown in a responsible way keeping it inside the engine failure return envelope as it goes out of shot, it returns to the video picture rotating rapidly probably indicating the failure of some part of the tail rotor system .
And the rotation starts first.
aart wrote:
An in-air explosion follows and strong rotation.
I’m not sure it is an explosion. More likely the landing lights become directed straight at the camera.
Reading about this, it appears to be a standard procedure whereby you depart backwards (so upon an engine or other failure you can transition to a forward direction descent and head back for the pad) and then from a specific height you transition to forward flight.
The failure would seem to have taken place around the transition point. Probably not the failure of one of the engines, so the thread title is probably not relevant.
aart wrote:
Is it me or is it flying out backwards?
It is. It was discussed at length on PPRuNe. It is a technique used when there are obstacles you can’t outclimb in forward flight. By flying out backwards rather than straight up the pilot keeps the take-off area in sight so that in case of an engine failure (s)he can immediately autorotate back to a landing.
Is it me or is it flying out backwards?
An in-air explosion follows and strong rotation.