Method of manufacturing and inspecting gas washed components in a gas turbine engine

A method of manufacturing a component having an in use gas washed surface, the method comprising:

• a) obtaining a reference component having a reference shape with an in use gas washed surface;
• b) setting one or more performance thresholds for the reference shape, the one or more performance thresholds defining an acceptable performance for the reference shape;
• c) obtaining a manufactured component made to the reference shape;
• d) measuring the manufactured component and determining a displacement distribution indicative of a geometric deviation of the manufactured component from the reference shape;
• e) determining a performance sensitivity distribution for the reference component, the performance sensitivity distribution having a plurality of points, each point being indicative of a performance factor for the reference component, the performance factor being a parameter that measures aerodynamic efficiency, isentropic efficiency, polytrophic efficiency, or an amount of flow over a part of a gas turbine engine including the gas washed surface;
• f) combining the performance sensitivity distribution and the displacement distribution to determine a performance prediction for the manufactured component;
• g) determining whether the performance prediction is within the one or more performance thresholds;
• h) accepting the manufactured component for use upon the performance prediction being within the one or more performance thresholds;
• and
• i) rejecting the manufactured component upon the performance prediction being outside the one or more performance thresholds.