hello I've been practising flying roter craft in FS2002 for quite a while now and I'm quite satissify with the result. (love to fly the default Bell a lot) One thing bother me thought, I never did a completly smooth landing even how hard I try. Until I replay my landing move and found out that the hello tend to "rest" on an invissible cussion of entity before it drop to solit ground and that made my landing non-smooth. (similar to riding a bull :-) ) So why does this happen?

Every action (a force) has an equal and opposite reaction. The same lift that supports an aircraft propels air downward. A helicopter would generate a significant downdraft as it slows to land. With any altitude this air column would have plenty of room to disapate.In a real helicopter I would expect close proximity to the ground to restrict the ability of air to flow out from under the aircraft. This restriction to the downdraft would reduce the downward velocity of air within the rotor disk. That would generate additional lift at the same throttle and collective settings. Maybe that factor is modeled in the simulator. The simulator does test for ground proximity, since it generates dust or spray effects away from airport pavement.Crew Member at FlightAdventures.com

wow, thx for extensive explanation. So it's something like a "ground effect" then. I'll try to be more sensitive on collective on landing then.