1-30 Change 2
Do not operate magnetic particle equipment within 36 inches of aircraft instruments.
Demagnetization of Inspection Parts. Following magnetic particle inspection of a part, the
residual magnetic field in the part shall be reduced to the lowest possible level. This must be done
prior to returning the part to service or rejecting it as a defective part. Unless this is done properly,
the residual magnetism may cause adverse influence on instruments, unnecessary wear on parts,
or attract ferrous metal chips and dust into bearing surfaces. After demagnetization, a magnetic field
strength meter shall be used to measure residual fields. Readings in excess of three units are not
188.8.131.52 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/yoke, about 24
inches before turning the probe off.
184.108.40.206 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 1-1500-335-23 (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.