Definition
A small, sharp metal point fitted to an aircraft's trailing edges and extremities that allows accumulated static electrical charge to bleed off into the surrounding air, reducing precipitation static buildup on the airframe.
Plain English
A tiny pointed rod attached to the back edges of the wings and tail that lets static electricity escape into the air before it builds up enough to cause radio interference.
Context Anchor
Seen in discussions of precipitation static, especially where rain, snow, ice, or dust can cause electrical charge to build up on the aircraft in flight.
Derivation
Discharge means to release or let out, from the Latin 'dis-' (away) and 'carricare' (to load) — literally to unload. A pin here is a slender, pointed metal piece. Together: a small point that lets the electrical 'load' escape.
Why Pilots Care
Prevents radio interference and corona discharge that can disrupt communications and navigation.
Analogy
A discharge pin is like a small drain for electricity. Instead of water leaving through a drain, static charge leaves through the pin into the air.
Intuition Check
Do not think of a discharge pin as a locking pin or fastener. In this context, its job is not to hold parts together; its job is to help release static electricity.
Example Sentence 1
During preflight, the pilot checked that the discharge pins on the trailing edges of the wings and stabilizer were intact and not broken off.
Example Sentence 2
During preflight the mechanic checked that none of the discharge pins were broken or missing.