An active clearance control system of a gas turbine engine includes a radially adjustable blade outer air seal system movable between a radially contracted Blade Outer Air Seal (BOAS) position that defines a first air volume and a radially expanded Blade Outer Air Seal (BOAS) position that defines a second air volume, the second air volume different than the first air volume. An accumulator system accommodate a difference in air volume between the first air volume and the second air volume.