John, I fly the Boeing Vertol H46. In BC we often are hovering in trees that are 150'+ high. The mass of the helicopter and the skill of the pilots
are enough to keep the cable movement down.
I agree that making a 70' hoist into a 220' hoist is making things worse. However, I think that making it into a 100' hoist may just give you better options. BTW, we have a 300 fpm hoist...may change things for some.
Engine failure in any hover, we have no recourse. If we're 150' above the ground with trees between or 180' doesn't make much difference to me.
Matthew.