Do not operate magnetic particle equipment within 36 inches of aircraft instruments.
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 3 units
are not acceptable.
18.104.22.168 Demagnetization Using AC.
If AC demagnetization
is selected, hold the part about
of the coil.
Move it slowly and steadily through the coil to at least 36 inches beyond end of 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
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 material. 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 automatic or manual film