FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 5. Nondestructive Inspection (NDI) | 5. Penetrant Inspection | 5-64. Technical Standards
AC 43.13-1B
9/8/98
blotter to assist the natural capillary action
bleed-out of the penetrant from discontinuities
and to spread the penetrant at discontinuity
surface edges to enhance bleed-out indications.
After the developer is applied, allow sufficient
time for the penetrant to be drawn out of any
discontinuities. Follow the manufacturer’s
recommendations.
j. Inspection for Discontinuities. After
the penetrant has sufficiently developed, visu-
ally inspect the surface for indications from
discontinuities. Evaluate each indication ob-
served to determine if it is within acceptable
limits. Visible penetrant inspection is per-
formed in normal visible white light, whereas
fluorescent penetrant inspection is performed
in black (ultraviolet) light.
k. Post-Cleaning. Remove inspection
material residues from parts after completion
of penetrant inspection. This residue could
interfere with subsequent part processing, or if
left on some alloys, it could increase their sus-
ceptibility to hydrogen embrittlement, inter-
granular corrosion, and stress corrosion during
service.
5-64. TECHNICAL STANDARDS. Two
of the more generally accepted aerospace in-
dustry standards are the MIL-I-25135E, In-
spection Materials, Penetrants (see table 5-6)
and ASTM-E-1417. The penetrant materials
specification (MIL-I-25135E) is used to pro-
cure penetrant materials and the process con-
trol specification (MIL-STD-6866) is used to
establish minimum requirements for conduct-
ing a penetrant inspection. Table 5-6 provides
a partial listing of commonly-accepted stan-
dards and specifications for penetrant inspec-
tion.
Page 5-34
Par 5-63