Or, as Whirls knows but is probably too busy sucking on a glass or two of vino to type, we can come down vertically but we have to keep our vsi low, which would then leave us in the avoid area of the h/v diagram (below the dead mans curve) for too long.much more importantly, if we did it and it all went pear-shaped then we'd be asked embarrassing questions and have to fill out paperwork, and I hate paperwork...high speed vertical descents are best left for high performance helicopters such as airwolf, budgie and harold...