I know its late in the day to add my 2 penneth to this thread but...
I made the mistake of touching the collective friction on my line check and the examiner went ballistic! ney F*$kin Berzzzzurk!
I only touched it as a " touch it so he can see your checking it..."!
ive only got a couple of hundred hours on R44 Raven 2, so will happily bow to the experienced pilots that do this for a living.
Regards
Skysmurf