FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 5. Nondestructive Inspection (NDI) | 1. General | 5-4. Training, Qualification, and Certification
AC 43.13-1B
9/8/98
college, or technical school, plus 2 years of
experience as a Level II in the applicable NDT
methods: or
flaws. The following paragraphs classify and
discuss the types of flaws or anomalies that
may be detected by NDI.
(3) The individual must have 4 years of
experience working as a Level II in the appli-
cable NDT methods and complete an exami-
nation.
5-4. TRAINING, QUALIFICATION, AND
CERTIFICATION. The success of any NDI
method and procedure depends upon the
knowledge, skill, and experience of the NDI
personnel involved. The person(s) responsible
for detecting and interpreting indications, such
as eddy current, X-ray, or ultrasonic NDI, must
be qualified and certified to specific FAA, or
other acceptable government or industry stan-
dards, such as MIL-STD-410, Nondestructive
Testing Personnel Qualification and Certifica-
tion, or Air Transport Association (ATA)
Specification 105-Guidelines for Training and
Qualifying Personnel in Nondestructive Test-
ing Methods. The person should be familiar
with the test method, know the potential types
of discontinuities peculiar to the material, and
be familiar with their effect on the structural
integrity of the part.
5-5. FLAWS. Although a specific discus-
sion of flaws and processes will not be given
in this AC, the importance of this area should
not be minimized. Inspection personnel
should know where flaws occur or can be ex-
pected to exist and what effect they can have in
each of the NDI test methods. Misinterpreta-
tion and/or improper evaluation of flaws or
improper performance of NDI can result in
serviceable parts being rejected and defective
parts being accepted.
All NDI personnel should be familiar with the
detection of flaws such as: corrosion, inherent
flaws, primary processing flaws, secondary
processing or finishing flaws, and in-service
a. Corrosion. This is the electrochemical
deterioration of a metal resulting from chemi-
cal reaction with the surrounding environment.
Corrosion is very common and can be an ex-
tremely critical defect. Therefore, NDI per-
sonnel may devote a significant amount of
their inspection time to corrosion detection.
b. Inherent Flaws. This group of flaws is
present in metal as the result of its initial so-
lidification from the molten state, before any
of the operations to forge or roll it into useful
sizes and shapes have begun. The following
are brief descriptions of some inherent flaws.
(1) Primary pipe is a shrinkage cavity
that forms at the top of an ingot during metal
solidification, which can extend deep into the
ingot. Failure to cut away all of the ingot
shrinkage cavity can result in unsound metal,
called pipe, that shows up as irregular voids in
finished products.
(2) Blowholes are secondary pipe holes
in metal that can occur when gas bubbles are
trapped as the molten metal in an ingot mold
solidifies. Many of these blowholes are clean
on the interior and are welded shut into sound
metal during the first rolling or forging of the
ingot. However, some do not weld and can
appear as seams or laminations in finished
products.
(3) Segregation is a nonuniform distri-
bution of various chemical constituents that
can occur in a metal when an ingot or casting
solidifies. Segregation can occur anywhere in
the metal and is normally irregular in shape.
However, there is a tendency for some con-
stituents in the metal to concentrate in the liq-
uid that solidifies last.
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