Definition
The outermost points of the airframe — the wingtips, the tail (vertical and horizontal stabilizer tips), the nose, propeller tips, and trailing edges of control surfaces. In the context of precipitation static, these are the locations where built-up electrical charge tends to discharge into the surrounding air.
Plain English
The far edges and tips of the aircraft — wingtips, tail, nose, and propeller tips. The points that stick out furthest from the main body.
Context Anchor
Seen in explanations of precipitation static, especially when describing where static charge tends to leave the aircraft and cause radio noise.
Derivation
From the Latin extremus, meaning 'outermost' or 'farthest.' In aviation it simply refers to the parts of the aircraft farthest from its center — the points that stick out into the airflow.
Why Pilots Care
These points are where static electricity builds up most readily, so proper dischargers here prevent radio interference and maintain reliable communications.
Grounding Statement
Picture charge building on the aircraft and escaping most easily from the tips, edges, and pointed parts exposed to the airflow.
Intuition Check
Extremities does not mean damaged, emergency, or unusual parts here. It means the outermost ends and exposed points of the aircraft.
Example Sentence 1
Static wicks are installed on the extremities of the aircraft so accumulated charge can dissipate into the air without disrupting the radios.
Example Sentence 2
Inspect the static wicks at the extremities of the aircraft before flight to ensure they are secure and undamaged.