hadn't thought of that for the upcoming book (Little Book of Autorotations),
Your fans are more than eagerly awaiting this! Going to happen in our lifetime?
It is my understanding (possibly wrong) that the practice lanes at BTA are paved with a "fine grained" asphalt that further reduces friction and the possibility of hooking a skid. IMHO, it is quite important to know what the nature of the surface is to which you are doing practice (touchdown) autos. Not all asphalt is created equal. Grooved runways at larger airports can ruin your day especially if you get a little yaw cranked in. Have been advised to use the (ungrooved) taxiways for this kind of thing, including run on landings and any other maneuvers where the helo may slide across the surface yawed from the direction of travel either as a result of poor technique or an emergency that doesnt readily permit a choice (possibly a hydraulics failure or tail rotor emergency).