Abstract: A system for ultrasonically testing the material of a turbine rotor includes a drive unit for axially indexing and angularly orienting a plurality of crystal transducers through the bore of the turbine rotor under test; an ultrasonic tester for electronically activating the crystal transducers as they are indexed through the rotor bore to transmit ultrasonic signals which are propagated through the rotor material and for receiving the back reflected echo signals corresponding to the ultrasonic transmissions; and a programmed electronic controller electrically interfaced to the drive unit and ultrasonic tester for adaptively coordinating the operation thereof in a selected one of a plurality of control modes to observe generated anomaly indications and measured test data parameters from the drive unit and ultrasonic tester which are used to determine the size and location of a detected potential imperfection in the rotor material and to adaptively control the drive unit in accordance with a function based on t