There are some high time FEs who do high hover engine failures; inc R22. Know of one who has demonstrated 12ft. But I think they lower the lever initially to preserve the RRPM; raising it again nearer the ground. That takes a lot of experience and presence of mind...
The aircraft is not in autorotation in a hover engine faillure practice, merely accelerating towards the ground. It takes 2-300 feet for the aircraft to fully establish in autorotation (watch the VSI accelerate then stabilise at a given ROD in an auto done from say 1500ft)
Doubt very much if there would be enough energy in the disk to cope with an engine failure at 12ft if the lever were left in the same position. And the odds of Joe pilot lowering the lever faced with a sudden acceleration to the ground seem slim.
TT
Last edited by PPRuNeUser129638; 10th December 2007 at 14:33.