Definition
A nondestructive testing method that uses an alternating-current coil to induce small circulating electrical currents (eddy currents) in a conductive part. Cracks, corrosion, or other flaws disturb the flow of these currents, and the resulting change is detected by the inspection instrument, allowing defects at or near the surface to be located without damaging the part.
Plain English
A way to check metal parts for hidden cracks or corrosion by holding a small probe against them. The probe creates tiny electrical swirls inside the metal, and the instrument shows when something disrupts those swirls.
Context Anchor
Seen in aircraft maintenance manuals, inspection procedures, and repair records when metal parts must be checked for cracks or corrosion.
Derivation
Eddy comes from an Old Norse-rooted English word for a small whirlpool or circular flow. The name fits because the induced electrical currents flow in tiny circular patterns inside the metal, similar to whirlpools in water.
Why Pilots Care
Identifies fatigue cracks and corrosion early, preventing in-flight structural failures on critical airframe and engine parts.
Analogy
Like sliding a metal detector over sand to find hidden objects, but the detector here senses tiny breaks inside the metal itself.
Grounding Statement
A technician moves a probe over the part, and the test equipment reacts differently when the metal beneath the probe is cracked, corroded, or otherwise changed.
Intuition Check
“Current” does not mean “present” or “latest” here. It means electrical flow inside the metal part being inspected.
Example Sentence 1
The technician used eddy current inspection to check the bolt holes on the wing spar for fatigue cracks.
Example Sentence 2
Routine eddy current inspection of the fuselage skin revealed a small crack missed by visual checks.