I flew the S61 for Bristow between 1990 and 2002 and the AFCS was always OFF when on the ground. It was disengaged immediately you lowered the collective on landing. A possible exception would be if you were doing circuits on an OPC say, where it could be left engaged as you were about to take off (ATC permitting) imminently.
As far as the company check-list was concerned, the last item on the take-off checks was AFCS ON and the first item on the after landing checks was AFCS OFF.
I seem to recall the reason for not having it engaged during ground taxi was to prevent the AFCS fighting with the moog valves in the aux hydraulic pack. Also, an AFCS hard-over on the ground would be too exciting for words if there was someone under the disc.
Certainly on a moving deck, if the AFCS was left engaged the rotor disc would try to maintain earth horizon rather than deck horizon. There was also the risk of the yaw channel making inputs unless the pedal micro-switches were pressed.
Last edited by XA290; 24th Jan 2013 at 20:19.