9 and 20 the closing movement 21 of the annular half 8 of the cowl is hence locked the maintenance operator is thus warned as he she can no longer finish his her closing movement he she needs to reopen the half 8 of the cowl operates the lever 9 until the end of travel of the bolting and finally resume the normal closing sequence of the cowl on fig9 to 12 it has been represented a second form of a member for locking the closing movement of the annular half of the cowl or one half of the cowl which is thus only possible when the locking member is retracted or rendered inactive because the lever 9 has been correctly closed in bolted position on fig9 it has been represented the lock with the locking member 20 thereof in a retracted or inactive position fig9 represents the same closed state of the nacelle as that of fig1 and the lock is identical to that of fig1 5 except for the locking member 23 the locking member of this second form is constituted by a piece composed of a rotational axis 24 returned by a spring correctly disposed in a retracted position when the stick or lever 9 has been correctly operated at the end of travel of the bolting by a maintenance operator the piece 23 then includes two symmetrical parts around the axis 24 each symmetrical part being in the shape of a cup or a hollow shape 25 or 26 on fig1 the nacelle is in.