Definition
A nondestructive inspection method for ferromagnetic parts in which the magnetizing current and the application of magnetic particles (wet bath or dry powder) occur at the same time. The current is held on while the particle medium is flowed over or dusted onto the part, so any flaws produce indications while the magnetic field is at its strongest.
Plain English
A way of checking iron or steel parts for cracks by running an electric current through them while pouring or dusting fine magnetic particles over the surface at the same moment. Cracks pull the particles together and show up as visible lines.
Context Anchor
Seen in aviation maintenance when inspecting steel engine parts, shafts, gears, and other parts that can be magnetized.
Derivation
Continuous here refers to the timing of the process — the magnetizing current is kept on continuously while the particles are applied, rather than being switched off first. This is what distinguishes it from the residual method, where particles are applied after the current is removed.
Why Pilots Care
Detects hidden cracks before they can cause in-flight engine failure, directly supporting airworthiness of critical powerplant parts.
Intuition Check
Continuous does not mean the inspection runs endlessly. Here it means the particles are applied while the part is actively being magnetized.
Example Sentence 1
The crankshaft was checked using continuous magnetic particle inspection because the shop wanted the highest sensitivity for detecting fatigue cracks.
Example Sentence 2
During the overhaul, continuous magnetic particle inspection showed no defects in the camshaft lobes.