Abstract: In a gas turbine engine having rotor blades which rotate with the blade tips in proximity with a surrounding rub strip in the engine shroud, an improvement is provided in the form of a radially adjustable rub strip-air bladder assembly. That is, an air bladder is mounted between the rub strip and the shroud and compressed air is fed to or withdrawn from the bladder to radially displace the rub strip so it can follow changes in the rotor blade length and maintain a close clearance with the tips of such blades under varying engine conditions, e.g. accels and decels, while minimizing contact of blade tips and rub-strip. The rub strip-bladder assembly is flexible and can react automatically to radially withdraw in advance of extending rotor blades as a pressure surge suddenly backs through such blades.