Originally Posted by
HeliComparator
That is what the report says, however....
VRS requires very low airspeed whereas they seemed to have 20-30kts, and VRS results in a rate of descent of maybe 6000'/min not responding to collective, whereas they had 1800.
Fully developed Vortex Ring will give you 6000', the report does state "...vortex-ring state
entry condition..." so 1000' to 1800'/Min is entirely reasonable. It also says that the ac went from 240' / 24%Tq / 1000' per min to 1800' per min by 100' even though he now had 115% Tq on. Sounds like pulling power made it worse, which could also indicate the onset of VRS.
Anyway "it" wasn't caused by any of the above, "it" was caused by prolonged inattention to the airspeed having previously intentionally destabilised the approach by substantially reducing power to slow down.
No arguments from me there though!
Anyway, as said, doesn't really matter as the real cause of the accident was failure to monitor the basics and perhaps an over reliance of AP.
Or perhaps an under reliance? Use of the 4th axis, IAS hold, would have prevented this. The L2 cannot match a 225 in the quality of its 4 axis ability, but it usually manages pretty well and there has to be a good reason not to use it in a scenario such as this.