Patent ID: 8439636

Claim:
A BOAS for a turbine in a gas turbine engine, the BOAS comprising: a turbine casing with a forward hook and an aft hook; a front retaining ring secured to an aft side of the forward hook; an aft retaining ring secured to an aft side of the aft hook; the front retaining ring having a lower flange with a surface to abut a forward end of an impingement plate; the aft retaining ring having a forward extending projection and a forward extending longer projection that together form a progressively decreasing height slot; a blade outer air seal having a conical shape; the impingement plate is a conical shaped full annular impingement plate with a forward end and an aft end; the forward end of the conical shaped impingement plate secured between the lower flange of the front retaining ring and a forward end of the blade outer air seal in a free floating assembly; and, the aft end of the conical shaped impingement plate secured between the forward extending longer projection and an aft end of the blade outer air seal in a fixed assembly.