18.104.22.168 Demagnetization Using AC. If AC demagnetization is selected, hold the part about 12 inches in front of the coil.
Move it slowly and steadily through the coil to at least 36 inches beyond the end of the coil while current is still flowing.
Repeat process as necessary. Rotate and tumble parts of complex configuration while passing through the coil field. All
parts can be demagnetized using a contour probe in the AC mode. Place the probe against the magnetized part with the
switch in AC position. Turn probe on and withdraw it from the part, or the part from the probe, about 24 inches before
turning the probe off.
22.214.171.124 Demagnetization Using DC. If DC demagnetization is selected, the initial demagnetizing field shall be higher
than, and in nearly the same direction as, the field reached during inspection. The field shall then be reversed and
decreased in magnitude, and the process repeated (cycled) until an acceptable low value of residual field is reached.
Whenever possible, parts that have been circularly magnetized shall be magnetized in the longitudinal direction before
being demagnetized. This procedure is limited to stationary equipment.
1.4.10 Radiographic (RT) Method.
Radiographic inspection shall be performed in accordance with the general application and techniques in TM 55-1500-
335-23 (Nondestructive Inspection Methods manual) and the specific requirements of this technical manual.
Radiographic inspection is used to detect internal and external structural details of all types of parts and materials. This
method is used for the inspection of airframe structure for damage, detection of moisture entrapment, structure
alignment, and foreign object intrusion. It can sometimes be used in areas otherwise inaccessible to other
nondestructive inspections and to verify indications observed by other methods.
Radiographic inspections are accomplished by passing the X-ray beam through the part or assembly to expose a
radiographic film emulsion or other sensitized medium. The processed film shows the structural details of the part by
variations in film density. Requirements for film density, image quality indicator, identification, and other factors are
specified in MIL-STD-453.
Film processing is a series of operations such as developing, fixing, and washing, associated with the conversion of the
latent image into a stable visible image and will be provided by manual or automatic film processing.
126.96.36.199 Safety Precautions During Radiographic Inspections. Follow safety precautions and instructions contained in
this manual and the Nondestructive Inspection Methods manual listed in Table 1-1.