NONDESTRUCTIVE INSPECTIONS, WELDING, AND HEAT TREATMENT

Chapter Objective: Upon completion of this chapter, you will have a basic knowledge of nondestructive inspection (NDI) methods, welding procedures and equipment, and the different forms of heat treatment.

In this chapter, we will discuss the basic principles and procedures of nondestructive inspections, welding, and the heat treatment of metals. These three areas require special training, and in the case of non-destructive inspections and welding, they require

special certification prior to performing these two functions. While not all AMs are required to become NDI operators, aeronautical equipment welders, or have the need to perform heat treatment of metal, there is the need to be familiar with these procedures and how they apply to the AM rate. The information in these areas is being presented in a broad nature. For a more detailed discussion of these procedures, refer to the applicable technical manuals.

NONDESTRUCTIVE INSPECTION PROGRAM 

Learning Objective: program and the various NDI personnel qualifications.

In the hands of a trained and experienced technician, nondestructive inspection (NDI) methods allow detection of flaws or defects in materials with a high degree of accuracy and reliability. It is important that you become fully knowledgeable of the capabilities of each NDI method, but it is equally important that you recognize the limitations of these methods. The non-destructive inspection methods covered in this chapter serve as tools of prevention, which allow defects to be detected before they develop into serious failures. During the inspection of aircraft, it is essential that faults are found and corrected before they reach catastrophic proportions. In applicable areas, NDI can provide 100-percent sampling with no affect upon the use of the part or system being inspected. The effective use of NDI will result in increased operational safety, and in many instances, dramatically reduce maintenance man-hour expenditures.

NDI is the practice of evaluating a part or sample of material without impairing its future usefulness. The methods used in naval aviation include, but are not limited to, visual or optical, liquid penetrant, magnetic particle, eddy current, ultrasonic, and radiographic. The success in their use depends heavily upon intelligent application and discriminating interpretation of results. NDi is performed only by qualified and currently certified NDI personnel, and in accordance with NA 01-1A-16, Nondestructive Inspection Methods manual. This is a general manual covering the theory and general applications of the various methods of NDI.

The Aircraft Nondestructive Inspection School, located at NATTC Memphis, Tennessee, provides NDI technician training for both military and civil service personnel. Career designated (grade E-4 and above) Navy aviation structural mechanics (AMSs), Marine Corps structural mechanics, and equivalent civil service personnel are eligible for the course. In addition, NDI operator training in liquid penetrant, magnetic particle, and eddy current methods; refresher training; and recertification of NDI technicians are provided by the Naval Aviation Depot (NADEP) and ACC/TYCOM designated NDI specialists. Information pertaining to curriculum, quota requests, obligated service require-ments, and, where applicable, convening dates is published in the NAVEDTRA 10500, the cognizant ACC/TYCOM. If the request is approved, the ACC/TYCOM will advise which NADEP is to be used.

Before candidates arc selected for NDI technician or operator training, and annually thereafter, they are required to have an eye examination. Military and civilian NDI personnel are identified as NDI specialists, technicians, or as operators.

NDI specialists are authorized by the ACC to provide training and certification/recertification of NDI technicians/operators. They also provide technical NDI services.

NDI technicians are personnel who have successfully completed the NDI course (C-603-3191) at Aircraft Nondestructive Inspection School at NATTC Memphis, Tennessee. NDI technicians are assigned NEC 7225/MOS 6044, and they are qualified and certified to perform liquid penetrant, magnetic particle, eddy current, ultrasonic, and radiographic methods of NDI. These personnel are normally assigned to IMAs. NDI technicians with 3 or more years of experience and who are currently certified and engaged in NDI on a regular basis may be authorized by ACCs to train and certify NDI operators for specific NDI applications. The ACC may also waive the 3-year experience requirement provided requests for this authorization are addressed to the ACC/TYCOM via the appropriate wing.

This request must include the technicians current qualification, experience history, and the specific technical directive/technical publication-directed NDI applications for which operator certification is to be provided. If approved, a copy of the ACC authorization will be attached to the technicians NDI certification record and maintained with his/her individual NDI record. Such authorizations remain in effect only as long as the currency of certification and NDI experience is maintained. Currently active NDI technicians require reccertification every 3 years.

Early recertification is authorized and encouraged to prevent expiration of certification during tours of deployed duty. Current certification of NDI technicians who are regularly engaged in all methods of NDI may be extended by ACCs for up to 1 year if circumstances warrant. NEC 7225 personnel who have been inactive in NDI for 1 year or more require recertification before resuming active NDI technician status. Recertification is provided by designated NADEPs or by ACC designated and qualified NAESU Navy federal civilian or military technical specialists.