A seal structure for a gas turbine engine, comprising: a vane ; a blade outer air seal adjacent to the vane ; and a brush seal disposed in a cavity defined at least partially by a first surface of the blade outer air seal and a second surface of the vane , the brush seal comprising: a bristle pack , and a backing plate coupled to the bristle pack ; characterized in that : the backing plate contacts the first surface of the blade outer air seal and the second surface of the vane ; and the first surface of the blade outer air seal comprises a radial surface of the blade outer air seal , the second surface of the vane comprises an axial surface of the vane , and the bristle pack contacts both the radial surface of the blade outer air seal and the axial surface of the vane ; or the first surface of the blade outer air seal comprises a first radial surface of the blade outer air seal , the second surface of the vane comprises second radial surface of the vane , and the bristle pack contacts both the first radial surface of the blade outer air seal and the second radial surface of the vane . a vane ; a blade outer air seal adjacent to the vane ; and a brush seal disposed in a cavity defined at least partially by a first surface of the blade outer air seal and a second surface of the vane , the brush seal comprising: a bristle pack , and a backing plate coupled to the bristle pack ; characterized in that : the backing plate contacts the first surface of the blade outer air seal and the second surface of the vane ; and the first surface of the blade outer air seal comprises a radial surface of the blade outer air seal , the second surface of the vane comprises an axial surface of the vane , and the bristle pack contacts both the radial surface of the blade outer air seal and the axial surface of the vane ; or the first surface of the blade outer air seal comprises a first radial surface of the blade outer air seal , the second surface of the vane comprises second radial surface of the vane , and the bristle pack contacts both the first radial surface of the blade outer air seal and the second radial surface of the vane . a bristle pack , and a backing plate coupled to the bristle pack ; characterized in that : the backing plate contacts the first surface of the blade outer air seal and the second surface of the vane ; and the first surface of the blade outer air seal comprises a radial surface of the blade outer air seal , the second surface of the vane comprises an axial surface of the vane , and the bristle pack contacts both the radial surface of the blade outer air seal and the axial surface of the vane ; or the first surface of the blade outer air seal comprises a first radial surface of the blade outer air seal , the second surface of the vane comprises second radial surface of the vane , and the bristle pack contacts both the first radial surface of the blade outer air seal and the second radial surface of the vane . the backing plate contacts the first surface of the blade outer air seal and the second surface of the vane ; and the first surface of the blade outer air seal comprises a radial surface of the blade outer air seal , the second surface of the vane comprises an axial surface of the vane , and the bristle pack contacts both the radial surface of the blade outer air seal and the axial surface of the vane ; or the first surface of the blade outer air seal comprises a first radial surface of the blade outer air seal , the second surface of the vane comprises second radial surface of the vane , and the bristle pack contacts both the first radial surface of the blade outer air seal and the second radial surface of the vane . <EOS>