Abstract: A variable area restrictor is disclosed that is a turbine engine contains a variable area restrictor to provide improved matching between the pressure required for aerofoil cooling and the somewhat lower pressure requirement for supplying air to the interstage seals and disc cavities, where a spring loaded valve assembly with a fixed minimum flow area is controlled by pre-setting a minimum dimension for the opening between an inlet and the housing or body of the valve. A pre-loaded spring maintains the lift at this minimum dimension until the pressure drop across the flow area exceeds a certain value. Above this critical pressure drop, the valve lifts, causing the flow area to increase, and thereby reducing the supply pressure that would be otherwise necessary to achieve a disc cavity flow adequate to maintain the temperatures within specifications.