Definition
A small switch, usually mounted on a helicopter collective or turboprop power lever, that allows the pilot to make fine, incremental adjustments to a system's setting -- most commonly engine or rotor RPM on a governor-controlled engine. Each press or hold of the switch nudges the governed value up or down by a small amount rather than commanding a large change.
Plain English
A switch the pilot taps to make small, gradual changes to engine or rotor speed. Instead of moving a lever a long way, the pilot just clicks the button and the setting drifts up or down slightly.
Context Anchor
Seen in helicopter cockpit controls and in discussions of rotor rpm control.
Derivation
Named for the short 'beep' style inputs the pilot makes -- quick, small taps rather than large continuous movements. The name describes how it is used, not what it controls.
Why Pilots Care
Precise RPM control keeps the rotor in its safe operating range, improves engine response, and ensures the aircraft is ready for autorotation if needed.
Analogy
Like tapping the volume buttons on a car radio for fine adjustments rather than turning a big knob.
Intuition Check
Do not think of a beep button as a warning or alarm button. Here, it is a control switch used to adjust rotor speed in small steps.
Example Sentence 1
After takeoff, the pilot used the beep button to trim the rotor RPM back into the green arc.
Example Sentence 2
During hover practice the instructor told the student to beep the RPM down slightly to reduce torque.