Stator vane assembly includes plurality of vanes arranged in circumferential array, radially proximal mounting portion, radially distal mounting portion, and first latching mechanism. Each of plurality of vanes extends radially between radially proximal mounting portion and radially distal mounting portion, with each of plurality of vanes being pivotally mounted between radially proximal mounting portion and radially distal mounting portion. Plurality of vanes is movable between first arrangement allowing gas to flow across vanes, and second arrangement blocking gas flow across vanes. Pivot axis of each of plurality of vanes is offset from the line of aerodynamic center of pressure of vane towards trailing edge of vane, and first latching mechanism holds plurality of vanes in first arrangement. Upon receipt of signal, first latching mechanism releases plurality of vanes so that gas flow through vane assembly causes plurality of vanes to move from first arrangement to second arrangement.