An apparatus and method for characterizing gas flow through features fabricated in a hollow part. A pressurized gas is applied to an interior of the part, and this gas pressure flows outward through features fabricated in the part. At the same time, a stabilizing pressurized gas is applied to an exterior part skin; and the stabilizing gas has a controlled temperature differential from the gas applied to the part interior. An infrared signature of escaping gas and the surrounding part skin is analyzed by a classification method. Analysis of this infrared signature classifies the relative flow rate, size and position of the feature fabricated in the part.

A system (10) for imaging a combustion turbine engine airfoil includes a camera (12) and a positioner (24). The positioner may be controlled to dispose the camera within an inner turbine casing of the engine at a first position for acquiring a first image. The camera may then be moved to a second position for acquiring a second image. A storage device (30) stores the first and second images, and a processor (32) accesses the storage device to generate a composite image from the first and second images. For use when the airfoil is rotating, the system may also include a sensor (40) for generating a position signal (41) responsive to a detected angular position of an airfoil. The system may further include a trigger device (42), responsive to the position signal, for triggering the camera to acquire an image when the airfoil is proximate the camera.