FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 5. Nondestructive Inspection (NDI) | 4. Magnetic Particle Inspection | 5-48. Magnetization
AC 43.13-1B CHG 1
9/27/01
b. Longitudinal. Longitudinal magneti-
zation is induced in a part by placing the part
in a strong magnetic field, such as the center of
a coil or between the poles of an electromag-
netic yoke. (See figure 5-12.) When using a
coil, optimum results are obtained when the
following conditions are met.
(1) The part to be examined is at least
twice as long as it is wide.
(2) The long axis of the part is parallel
to the axis of the coil opening.
(3) The area of the coil opening is at
least 10 times the cross-sectional areas of the
part.
(4) The part is positioned against the
inner wall of the coil.
(5) Three to five turns are employed for
hand-held coils formed with cables.
(6) For the 10-to-1 fill factor, the effec-
tive region of inspection is 1 coil radius on ei-
ther side of the coil with 10 percent overlap.
(Refer to ASTME-1444.)
FIGURE 5-12. Longitudinal magnetization.
Page 5-24
Par 5-48