ULTRASONIC MAINTENANCE INSPECTION OF AIRCRAFT STRUCTURES

As part of the maintenance program for the DC-10 aircraft, the Douglas Aircraft Co. prepared the DC-10 Nondestructive Testing Manual. In this manual are numerous examples of ultrasonic inspection requirements for various parts of the aircraft structure. To adequately define these inspections, various techniques had to be evaluated and developed. This paper describes a variety of techniques for straight, angle and surface beam inspections. To assure proper instrument setup and sensitivity, a variety of ultrasonic reference standards are illustrated. Theoretical and experimental methods for generating the desired wave modes are presented. The paper also presents techniques for measuring depth of corrosion and for detecting debonds in adhesive bonded structures.