In IMAC there are two things absolutely required for a snap roll:

1) the nose MUST depart the line of flight in the proper direction (towards the canopy in a positive snap, towards the wheels in a negative snap).

2) the plane MUST autorotate.

If EITHER one is absent, the maneuver gets a zero.

Autorotation is a result of the wing being partially stalled (usually one wing) and it causes a rotation that is generally faster than could be accomplished by the use of the controls alone. Be watchful for the crafty pilot that will try to fool you with a little flick of the nose and then a REALLY fast axial roll instead of autorotation. Autorotation is very hard to define, but once you have seen it there is no mistaking it for a fast axial roll.

As a judge it matters not one little bit what controls are used, how much or in what direction. ALL you are doing is judging what the plane does. The figure in the original post would have been zeroed by me as well. It did not autorotate. I don't care if it was "wrong" rudder or whatever. The pilot failed to present the required components for a snap to get scored. Period.

There is a very nice section of a thing I call "The Rulebook" that covers this. It is worth a look!!.

Bill Malvey
Chairman IMAC Rules and Standards Committee