Aviation Dictionary
محدوده بتا، محدوده عمل موتور توربینی ملخ دار که بر اثر تغییرگام ملخ نیروی کششی معکوس یا صفر تولید شود
The beta range is used for ground operations inclusive of slowing the aircraft after landing. Below flight idle, the power levers control the blade pitch directly. With the power lever(s) in the ground idle position, the blade pitch is such that the propeller produces its minimum level of thrust.