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 | 5-62. Basic Steps to Perform Penetration Inspection
AC 43.13-1B
TABLE 5-5. Pre-cleaning methods for penetrant inspection.
9/8/98
METHOD
Mechanical Methods
USE
Abrasive tumbling
Removing light scale, burrs, welding flux, braze stopoff, rust, casting mold, and
core material; should not be used on soft metals such as aluminum, magnesium,
or titanium.
Dry abrasive grit
blasting
Removing light or heavy scale, flux, stopoff, rust, casting mold and core material,
sprayed coatings, carbon deposits: In general, any brittle deposit. Can be fixed
or portable (may peen metal over defect).
Wet abrasive grit
blast
Same as dry except, where deposits are light, better surface and better control of
dimensions are required.
Wire brushing
Removing light deposits of scale, flux, and stopoff (may mask defect by displac-
ing metal).
High pressure water
and steam
Ordinarily used with an alkaline cleaner or detergent; removing typical machine
shop contamination, such as cutting oils, polishing compounds, grease, chips,
and deposits from electrical discharge machining; used when surface finish must
be maintained.
Ultrasonic cleaning
Ordinarily used with detergent and water or with a solvent; removing adhering
shop contamination from large quantities of small parts.
Chemical Methods
Alkaline cleaning
Removing braze stopoff, rust, scale, oils, greases, polishing material, and carbon
deposits; ordinarily used on large articles where hand methods are too laborious;
also used on aluminum for gross metal removal.
Acid cleaning
Strong solutions for removing heavy scale; mild solutions for light scale; weak
(etching) solutions for removing lightly smeared metal.
Molten salt bath
cleaning
Conditioning and removing heavy scale; not suitable for aluminum, magnesium,
or titanium.
Solvent Methods
Solvent wiping
Same as for vapor degreasing except a hand operation; may employ nonhalo-
genated (nonchlorinated) solvents; used for localized low-volume cleaning.
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