Pootling along in the South West of England in a Wessex 5 when the rudder pedals locked. I disengaged the ASE but no change. I thought about switching off the hydraulics in turn but thought, no. I did a straight in approach to St Mawgan and ran on at around 80 knots, turned off the runway into dispersal using brakes and shut down on the run in. Re-started - problem gone...............never did find out what happened.