FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 5. Nondestructive Inspection (NDI) | 6. Radiography (X-Ray) Inspection | 5-83. Safety
9/8/98
AC 43.13-1B
a. The ability to inspect for both internal
and external flaws.
b. The ability to inspect covered or hid-
den parts or structures.
c. The ability to detect significant varia-
tions in composition.
d. Provides a permanent recording of
raw inspection data.
5-81. FLAWS. Certain types of flaws are
difficult to detect by radiography. Cracks can-
not be detected unless they are essentially
along the axis of the radiation beam. Tight
cracks in thick sections may not be detected at
all, even when properly oriented. Minute dis-
continuities such as: inclusions in wrought
material, flakes, microporosity, and microfis-
sures may not be detected unless they are suf-
ficiently segregated to yield a detectable gross
effect. Delaminations are nearly impossible to
detect with radiography. Because of their un-
favorable orientation, delaminations do not
yield differences in adsorption that enable
laminated areas to be distinguished from de-
laminated areas.
5-82. FIELD INSPECTION. The field in-
spection of thick sections can be a time-
consuming process, because the effective
radiation output of portable sources may re-
quire long exposure times of the radiographic
film. This limits field usage to sources of
lower activity that can be transported. The
output of portable x-ray sources may also limit
field inspection of thick sections, particularly
if a portable x-ray tube is used. Portable x-ray
tubes emit relatively low-energy (300 kev) ra-
diation and are limited in the radiation output.
Both of these characteristics of portable x-ray
tubes combine to limit their application to the
inspection of sections having the adsorption
equivalent of 75 mm (3 inches) of steel maxi-
mum. Portable linear accelerators and be-
tatrons that provide high-energy (> 1 MeV)
x-rays can be used for the radiographic field
inspection of thicker sections.
5-83. SAFETY. Radiographic safety re-
quirements can be obtained from; the OEM’s
manual, FAA requirements, cognizant FAA
ACO engineers, and radiation safety organiza-
tions such as the Nuclear Regulatory Commis-
sion (NRC). Information in radiation safety
publications can be used as a guide to ensure
that radiation exposure of personnel involved
in radiographic operations is limited to safe
levels, and to afford protection for the general
public.
5-84.5-88. [RESERVED.]
Par 5-80
Page 5-39 (and 5-40)