Aviation Maintenance Inspection Concepts

Outside micrometer, inside micrometer, depth micrometer, and thread micrometer.

Depending on the tool, some are calibrated every 6 months, while others are calibrated every 12 months.

Fluorescent or visual dye penetrant.

Any fault within a material will change the material's resonant frequency. Comparing the resonant frequency of a known sound material with the material under test will indicate the presence of a fault.

Clean the part thoroughly, apply the penetrant, and allow it to soak for the recommended dwell time. Remove all of the penetrant from the surface and apply the developer.

In the aircraft manufacturer's maintenance manual and Instructions for Continued Airworthiness (ICA).

Eddy current inspection.

X-ray inspection.

Magnetic particle inspection.

Ultrasonic inspection.

Any grease or dirt in a fault will keep the penetrant from seeping into the fault.

Thoroughly clean the part, magnetize it as directed by the appropriate service manual, flow the indicating medium over the surface, and inspect it under a "black" light. When the inspection is complete, thoroughly demagnetize the part.

To detect faults that extend across as well as lengthwise within the part.

Lengthwise.

If the parts are not completely demagnetized, they will attract steel particles that are produced by engine wear and will cause damage to bearing surfaces.

A current is induced into the metal being tested by a test probe. The amount of induced current is determined by the conductivity, mass, and permeability of the material, and the presence of any faults or voids.

To prevent magnetized parts from attracting filings, grindings, chips, or other steel particles, which can cause scoring, damage, and premature wear.

Incorrect measurement of close tolerance components can lead to failure of critical parts and assemblies.

Measuring equipment that is out of calibration can result in incorrect measurements, which can lead to component and system failure.

Incorrect inspection techniques will lead to the aircraft or component not being inspected in accordance with the manufacturer's specifications, which can lead to failure of the inspected item.

Incorrect use of a multimeter can cause damage to the multimeter and/or result in incorrect conclusions regarding the circuit or component being tested. When used as an ohmmeter, the component being measured must be isolated (disconnected) from the circuit. If the multimeter is set for measuring current, and the leads are placed across any voltage drop, the meter can be damaged. A thorough understanding of the circuit being tested is critical for proper troubleshooting.