Definition
A discoloration that occurs when dyes or stains from an underlying surface migrate up through freshly applied dope coatings on a fabric-covered aircraft, producing visible streaks or spots in the finish.
Plain English
When color from the material underneath seeps up into the wet finish being painted on top, leaving stains in the new coat.
Context Anchor
Seen in aircraft fabric covering and finishing work, especially when choosing or applying colored coatings over fabric.
Derivation
‘Dope’ here refers to the liquid finish (a lacquer-like coating) brushed or sprayed onto aircraft fabric to tighten and seal it; the word comes from the Dutch ‘doop’ meaning a dipping liquid or sauce. ‘Bleeding’ is used in the painter’s sense — color seeping through a fresh coat — not in any medical sense.
Why Pilots Care
For maintenance technicians, bleeding ruins the appearance and may indicate the surface was not properly sealed before doping; it usually requires stripping and refinishing to correct.
Analogy
It is like drawing with a dark marker, painting over it with a light color, and then seeing the marker color show through the paint.
Intuition Check
Do not read “bleeding” as blood or “dope” as a drug. Here, “bleeding” means color seeping through, and “dope” means an aircraft fabric coating.
Example Sentence 1
The technician sealed the patched area with aluminum-pigmented dope first to prevent bleeding dope from staining the silver topcoat.
Example Sentence 2
They switched to a different brand of dope to stop the bleeding that had appeared on the lower wing.