A method & apparatus for conveying an ultrasonic sensor about an outer peripheral surface of a tube to perform a non-destructive evaluation thereof is disclosed. The ultrasonic sensor is mounted on a flexible tension link and the method involves extending the flexible tension link while urging an extended portion of the flexible tension link towards the outer peripheral surface of the tube at a plurality of locations along it's length, thereby causing the ultrasonic sensor to move through an arc in a direction circumferentially around the tube while maintaining ultrasonic coupling between the ultrasonic sensor and the tube.