Blade mounting system with back-up retention formation

A mounting system for mounting a blade 70 to a rotor body includes a pitch control mechanism having an anchor 76 and a pitch change rod 75 extending radially outwardly from the anchor to join to a base of the blade. The anchor and the rod are rotatable about the longitudinal axis of the rod to vary the blade pitch. The pitch control mechanism further includes a torque-transmitting formation 77a, 77b between the blade and the anchor such that pitch-varying torque can be transmitted to the blade through the torque-transmitting formation while allowing relative radial movement between the blade and the anchor. A primary bearing formation 80a, 80b transmits blade centrifugal loads to the rotor body while accommodating variation of the blade pitch. A secondary bearing formation 81 transmits pitch change mechanism centrifugal loads to the rotor body while accommodating rotation of the anchor and the rod during variation of the blade pitch. In normal operation, the radial spacing of the anchor and the blade is maintained by the primary and secondary bearing arrangements. A back-up retention formation (79a,79b Fig 3) which, on failure of the primary bearing formation leading to outward radial movement of the blade relative to the anchor, activates to divert blade centrifugal loads through the secondary bearing formation to the rotor body.