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Andrew Smith
NDI - Non-destructive Inspection
Question | Answer |
---|---|
Visual Inspection | An inspection of an Aircraft, parts, units, components, that do not alter or destroy teh physical or material properties or integrity fo the part. |
Non-destructive testing | Visual means, it is the oldest method of inspection. |
Non-destructive testing tools | Basic tools are flash light, mirror, and magnifying glass. Telescope and Borescope are also used in inspecting. |
Borescope | Typically used to inspect the inside of engines or components |
Weld inspections | Uniformed in width, Ripples are evenally feathered, Show no burn due to over heating, Should be 100% penetration on butt weld. |
Eddy Current Inspection | A testing methof that requires little or no pat penetration and can detect surface and sub-surface flaws in most metals. |
Eddy current material properties | Conductivity of material, Demensional factors, Discontinuities, Permeability. |
Liquid Penetrant Inspection, Dye Penetrant Inspection | Usable on ferrous and non-ferrous metals and non-porous plastics. Will detect surface cracks or porosity |
Penetrant Dis-advantage | The defect must be open to the surface in order to let penetrant get into the defect. |
Pentrant Appication | Visibility of penetrant in material increased with the addition of DYE. 2 types - Visible or Fluoresent dyes. |
Liquid dye penetrant | Dye process is based on the principle of CAPILLARY ATTRACTION |
Fluorescent dye | Capable of emitting visible light when exposed to near Ultraviolet or Black Light. |
Visual and Dual Mode penetrant | Red in color and viewed in natural or white light. Red Fluorescent. |
Interpetation Results of penetrants | 1. If all penetrant are washed out of defect an indecation cannot be formed. 2.Smaller defects require longer penetration time. 3. Penetrant developer when applied to surface part will dry to a smooth even white coating. As it dries bright red indications |
Ultrasonic Inspection | 1. The only form of NDI/NDT used on plastic, ceramics, and most metals. 2. Possible to locate defects in all types of materials without damaging material being inspected. |
Ultrasonic systems - 2 types | The Pulsed and the Resonance system. |
Xray Inspection and Gamma Ray Radiograph Inspection. | Use the ability of Electromagnetic Radiation to examine the interior of objects. |
Gamma Rays | Most damaging type of rediation in Aircraft maintance, can penetrate into the human body. They are produced only when electrons are flowing within a tube. Gamma rays cannot be shut off, controled, or directed. |
Magnetic Particle Inspection | 1. method of detecting invisible cracks and other defects in Ferrousmagnetic materials. 2. Not applicableto non-magnetic materials |
Magnetic Orientation | 1. ensure flux line are nearly perpindicular to a flow a part should be magnetized both longitudely and circularly. |
Testing Mediums for magnetic particle inspection | Divided into 2 types: WET and DRY process materials |
Continous Method | Requires that the part being inspected to the magnetic force when the testing medium is applied. Inspect the part while magnetized. |
Demagnetization | Before a part is to return to service it is demagnetized throughly. If not it could be detrimental to the opperation of the Aircraft. The part could dras foreign material toward itself thus causing a destructive process |