anne - a lot of people do not realise that the engines sometimes appear to be 'idling' but it is just the wind turning the blades.
Regarding the rudder, depending on the way a (powered) rudder assembly is controlled, there is normally a 'hydraulic lock' inside the rudder actuator so that the rudder control cannot move even when hydraulic pump pressure is removed. Some a/c may not have this in their design OR the 'lock' may dissipate with time through seepage of fluid .