Definition
An adjustable mechanical resistance device on a helicopter's collective control that allows the pilot to set how much force is required to move the collective, or to hold it in a chosen position so it does not creep up or down on its own.
Plain English
A knob or lever the pilot tightens to make the collective stick stiffer, so it stays where it is set instead of drifting.
Context Anchor
Encountered in helicopter control discussions, especially when setting or checking the collective before flight and while maintaining steady power in instrument flight.
Derivation
Collective refers to the helicopter control that changes the pitch of all main rotor blades together (collectively). Friction here means adjustable mechanical resistance, not the everyday idea of two surfaces rubbing.
Why Pilots Care
Allows the pilot to hold a chosen collective position during instrument flight or other tasks without constant manual effort.
Intuition Check
Do not read friction here as a mechanical problem or damage. In this context, friction is an intentional adjustable resistance that helps the collective lever stay in place.
Example Sentence 1
Before takeoff, the pilot reduced collective friction so the control would move freely during the hover.
Example Sentence 2
Before starting the climb, the instructor eased off the collective friction for smoother power changes.