Gas turbine engines include one or more turbine stages. Each stage includes a plurality of blades mounted to a disc that is fixed for rotation with a turbine shaft. Adjacent to each set of blades is a set of vanes that are fixed to an engine casing. Blade outer air seals (BOAS) are positioned radially outward of tips of the blades and extend between adjacent sets of vanes. Seals extend between the vanes and the blade outer air seals to facilitate sealing the gas path.
Seals that are located close to the gas path are susceptible to wear. Loss of material due to wear can degrade the seal and reduce sealing spring force. This can eventually lead to permanent deformation of the seal, resulting in loss of sealing.