Definition
The range of low or negative blade angles on a constant-speed turboprop or reversible propeller, used during ground operations to produce zero or reverse thrust. In the beta range, the pilot directly controls blade angle with the power lever rather than allowing the propeller governor to set it automatically based on RPM.
Plain English
Beta is the part of the propeller's blade-angle range used on the ground, where the pilot moves the blades to a flat or reversed angle to slow down, stop, or back the aircraft up. In this range, the pilot is setting the blade angle directly instead of letting the governor handle it.
Context Anchor
Seen in aerodynamics, flight-test discussions, and explanations of slips, skids, and yaw.
Derivation
Beta is the second letter of the Greek alphabet (β), commonly used in engineering as a symbol for an angle. Here it specifically refers to propeller blade angle, so 'beta range' literally means 'the blade-angle range' the pilot controls directly.
Why Pilots Care
Beta allows controlled taxi speeds and runway deceleration while reducing brake wear and the risk of propeller overspeed on the ground.
Intuition Check
Beta does not mean a software test version here. In this aviation use, it is a symbol for sideways angle between the airplane and the airflow.
Example Sentence 1
After touchdown, the pilot brought the power levers into beta to flatten the blades and shorten the landing roll.
Example Sentence 2
During taxi the instructor demonstrated beta range to keep speed low while the engines remained at idle.