Rotary control system for an apparatus, the system comprising: - a rotary control member which is movable in rotation about a first fixed axis, between first and second positions, - a rotary control handle which is to be secured in rotation to the rotary member about the first axis, - a blocking device which is selectively displaceable, when the rotary member is in its first position, between: ∘ a blocking configuration, in which it prevents the rotary member from being displaced towards its second position, and ∘ a release configuration, in which it allows the rotary member to be displaced towards its second position, the system being characterised in that it further comprises a locking plate which is movable in rotation about the first axis relative to the rotary member, when the rotary member is in its first position, between: ∘ a locking position, in which a first through-orifice of the rotary member is superposed with a second through-orifice of the locking plate, the first and second orifices then forming an opening capable of receiving a locking tool which secures the rotary member in rotation with the locking plate about the first axis, and ∘ an unlocking position, in which the first and second orifices (56, 84) are offset relative to one another and do not together form the opening, and in that the locking plate is configured to switch the blocking device between its blocking and release configurations when it is displaced between its locked and unlocked positions, respectively. - a rotary control member which is movable in rotation about a first fixed axis, between first and second positions, - a rotary control handle which is to be secured in rotation to the rotary member about the first axis, - a blocking device which is selectively displaceable, when the rotary member is in its first position, between: ∘ a blocking configuration, in which it prevents the rotary member from being displaced towards its second position, and ∘ a release configuration, in which it allows the rotary member to be displaced towards its second position, the system being characterised in that it further comprises a locking plate which is movable in rotation about the first axis relative to the rotary member, when the rotary member is in its first position, between: ∘ a locking position, in which a first through-orifice of the rotary member is superposed with a second through-orifice of the locking plate, the first and second orifices then forming an opening capable of receiving a locking tool which secures the rotary member in rotation with the locking plate about the first axis, and ∘ an unlocking position, in which the first and second orifices (56, 84) are offset relative to one another and do not together form the opening, and in that the locking plate is configured to switch the blocking device between its blocking and release configurations when it is displaced between its locked and unlocked positions, respectively. ∘ a blocking configuration, in which it prevents the rotary member from being displaced towards its second position, and ∘ a release configuration, in which it allows the rotary member to be displaced towards its second position, ∘ a locking position, in which a first through-orifice of the rotary member is superposed with a second through-orifice of the locking plate, the first and second orifices then forming an opening capable of receiving a locking tool which secures the rotary member in rotation with the locking plate about the first axis, and ∘ an unlocking position, in which the first and second orifices (56, 84) are offset relative to one another and do not together form the opening,