Fan for an aircraft cooling unit

A Fan (16), in particular for an aircraft cooling unit, having a wheel (128) comprising a hub (138) and an annular array of blades (140), a shaft assembly (136) for driving the wheel about an axis (A), and fusible means for connecting the hub of the wheel to the shaft assembly, said fusible connecting means comprising a first mounting sleeve through which the shaft assembly extends and which is surrounded by the hub, and fusible safety elements (174) which extend parallel to the axis (A) and are configured to break and to disengage the wheel from the shaft assembly when said wheel rotates anda driving torque of the wheel transmitted by the shaft assembly exceeds a certain threshold, characterised in that the connecting means comprise a second wearing sleeve (143) which is inserted betweenthe first sleeve and the hub and through which the fusible elements extend, the second sleeve being made of a material which is different from that of the first sleeve and subject to wear by frictionand/or by heating if the s