Definition
On a turboprop engine, the range of power lever positions in which propeller blade pitch is controlled directly by the pilot rather than by the propeller governor. The beta range is used for ground operations only — typically taxiing, landing rollout, and reverse thrust — and includes blade angles from flat pitch through reverse.
Plain English
The part of the power lever's travel where the pilot is moving the propeller blades to flatter or reversed angles by hand, instead of letting the automatic governor set the blade angle. It is only used on the ground.
Context Anchor
Seen in turboprop operation during taxi, landing rollout, ground idle, and reverse-thrust discussions.
Derivation
In propeller engineering, Greek letters are used to label different blade angle regimes. 'Beta' (β) is the symbol for the geometric blade angle itself, so 'beta range' literally means the range where the pilot is directly controlling that blade angle.
Why Pilots Care
Selecting beta range lets the pilot stop or maneuver the airplane without heavy brake use and prevents the propeller from driving the engine in reverse.
Grounding Statement
In beta range, the pilot is mainly changing how the propeller blades bite the air, not just adding or reducing normal flight power.
Intuition Check
Beta range does not mean a second normal power setting for flight. It means the low blade-angle range used mainly on the ground, below the normal flight-idle propeller setting.
Example Sentence 1
After touchdown, the pilot lifted the power levers over the gate into the beta range to slow the airplane on the runway.
Example Sentence 2
While taxiing to the ramp the pilot used beta range to make small speed adjustments without touching the brakes.