Energy absorbing fan blade spacer

A gas turbine engine fan section (24) is disclosed that includes a hub (28). Circumferentially spaced fan blades (30) are supported on the hub (28). A spacer (40) is arranged between adjacent fan blades (30) and is operatively supported by the hub (28). The spacer (40) is configured to be collapsible in response to a fan blade load exerted on the spacer (40) in excess of a threshold load. The spacer (40) is generally rigid at fan blade loads below the threshold load.