Definition
The range of turboprop propeller blade angles in which the pilot directly controls blade pitch with the power lever, rather than the propeller governor controlling pitch to maintain a constant RPM. The beta range typically covers ground operations: taxi, reverse, and low-power maneuvering on the ramp. Within this range, moving the power lever changes blade angle directly, which in turn changes the load on the engine and the thrust produced.
Plain English
On a turboprop, this is the band of propeller blade angles used on the ground where the pilot's lever moves the blades directly, instead of an automatic system holding the engine at a steady RPM. It is what gives a turboprop its fine taxi control and reverse thrust.
Context Anchor
Seen in turboprop operating procedures, especially around power-lever use after touchdown, during landing rollout, and during taxi.
Derivation
In propeller engineering, Greek letters label different control modes: alpha is the in-flight governed mode, and beta is the direct-pitch mode used on the ground. The label simply marks it as the second mode of operation.
Why Pilots Care
Provides powerful, immediate reverse thrust for stopping and precise taxi control without heavy brake use, shortening landing distance and reducing brake wear.
Grounding Statement
After touchdown in a turboprop, moving the power levers into the beta control range can make the propellers help slow the airplane by changing blade angle.
Intuition Check
Beta does not mean a test version here. In this context, beta refers to propeller blade angle and the range where that angle is controlled directly by the power lever.
Example Sentence 1
After touchdown, the pilot brought the power lever back into the beta control range to slow the aircraft on the runway.
Example Sentence 2
The instructor demonstrated how small movements in the beta control range let the pilot taxi at exactly the right speed without riding the brakes.