Definition
A luminous electrical discharge, also known as St. Elmo's fire, that appears as a glowing blue or violet light around pointed objects on an aircraft (such as wingtips, propeller tips, antennas, and windshield edges) when flying through a strongly charged atmosphere, typically near thunderstorms or in heavy precipitation.
Plain English
A harmless glow that sometimes appears around the edges and tips of an aircraft when flying through air with a strong electrical charge. It looks dramatic but does not damage the airplane.
Context Anchor
A pilot may encounter this term in weather, thunderstorm, or aircraft electrical-effect discussions, especially when reading about flight near strongly charged clouds.
Derivation
From the Italian 'corpo santo,' meaning 'holy body.' Sailors centuries ago saw the same glow on ship masts during storms and believed it was a sign of protection from St. Elmo, the patron saint of sailors. Knowing this helps the term feel less mysterious -- it's the same phenomenon, just observed on aircraft instead of ships.
Why Pilots Care
It warns that the aircraft is in a highly charged electrical field that may precede lightning, though the glow itself is harmless.
Analogy
It is a little like the faint glow that can appear near very high-voltage equipment, except on an aircraft it happens because the surrounding air is strongly charged.
Grounding Statement
Picture a dim bluish glow around a propeller tip, windshield edge, antenna, or wingtip while flying near stormy clouds.
Intuition Check
Do not treat a corposant as fire on the aircraft. It is an electrical glow in the air around the aircraft, usually associated with strongly charged weather.
Example Sentence 1
While flying through heavy snow at night, the crew watched corposant dance along the windshield and propeller tips.
Example Sentence 2
A faint corposant appeared along the wing leading edge, confirming the presence of strong static charge.