Hopefully, you've been looking out and adjusting the groundspeed as you go down. My own choice is to wait till about 70 feet. If it helps, here is an edited version of the autos section from The Helicopter Pilot's Handbook:
"For a clear area, when about 70 feet from the ground, use rearward cyclic to slow down vertically and horizontally. The amount is proportional to your speed and serves to increase the total lift reaction (which stops the sink) and shifts it to the rear (which stops forward movement). It also increases the rotor RPM.
Continue the flare progressively to a nose-high attitude (in a 407, the instrument panel should just about hide the horizon), applying collective as flare effect decreases to allow the machine to flop forward in a self-levelling process, watching for drift. The “check”, which is a more positive application of collective, is only used with some helicopters to level the attitude better. Otherwise, there should only be small pause in a continuous movement, and you should find the rear skids touching the ground gently well before you run out. Get used to the visual clues required for the correct approach and flare attitude – there's no time to look at the ASI, and the one on the 407 is dampened anyway, so is fairly useless under these circumstances. Get up on a nice day and practice autos to a cloud, getting used to the horizon's position through the screen during descent, flare and turns on your machine.
In every flare there is a point called the apex, which is where the trading off of airspeed for lift is essentially all over and you just have to get yourself on the ground. Put another way, it is the point where there is no further benefit from the flare manoeuvre, so you may as well pull the pitch (a little later in a 206). As the flare ends, and the kinetic energy of the rotors is used when the collective is raised, the airflow through the rotors is reversed, assisting the level, ready to cushion the landing with collective. This is where correct use of airspeed during the descent will have had the most beneficial effects—as the kinetic energy stored in the blades is what slows you down, it follows that any you have used already to slow an unnecessarily fast descent is not available for the final stages of touching down."
Hope that helps
Phil
Last edited by paco; 15th April 2002 at 12:39.