Definition
A trade name for a fluorescent penetrant inspection process used to detect surface cracks and other discontinuities in nonporous metal parts. A fluorescent dye is applied to the part and drawn into any surface defects by capillary action. After the excess is wiped off and a developer is applied, the part is examined under ultraviolet (black) light, causing any trapped dye to glow brightly and reveal the flaw.
Plain English
A way of finding tiny cracks in metal aircraft parts. Technicians coat the part with a special dye that seeps into any cracks. They wipe off the surface and shine a black light on it. Cracks light up brightly so they can be seen clearly.
Context Anchor
Seen in aircraft maintenance and inspection records, especially when checking metal parts for surface cracks.
Derivation
Zyglo is a brand name from Magnaflux Corporation, combining 'Zy' (no specific meaning) with 'glo' (glow), referring to how the dye glows under ultraviolet light. The 'Wink' portion refers to the specific Wink-brand variant of the process.
Why Pilots Care
Cracks in metal parts often start far too small to see with the naked eye. A missed crack in a critical component like a propeller hub or landing gear can lead to catastrophic failure. Knowing that this kind of inspection exists helps pilots understand what their mechanic is doing and why certain inspections take time.
Grounding Statement
The basic idea is to make a hidden surface opening hold a glowing liquid so the opening becomes visible.
Intuition Check
Do not read Wink Zyglo as an ordinary phrase. It is a trade-name inspection process, not a visual signal or a type of aircraft light.
Example Sentence 1
The mechanic ran a Wink Zyglo inspection on the propeller blades after the prop strike to confirm there were no hidden cracks.
Example Sentence 2
Any bright fluorescent lines found during the Wink Zyglo check required the part to be rejected and replaced.