Abstract: A retainer for securing the outer air seal assembly of a turbine rotor stage in a locked position. The outer air seal is suspended from the turbine casing over the rotor stage and is locked to the casing by annular segmented locking keys. A series of circumferentially spaced seats are located upon the front face of the locking key segments with the outer surfaces of the seats describing a circle approximating a first diameter. A split ring retainer is slidably carried in a radially disposed groove and is arranged to secure the key segments in a locked position. A series of lugs extend inwardly from the inside wall of the ring. The lugs are circumferentially spaced about the ring with the inner surface of the lugs approximating a circle having a second diameter that is less that of the first diameter approximated by the seats. The lugs are spaced so that each lug can be seated upon a seat to flex the ring outwardly in a radial direction and thus secure the key segment in a locking position.