PT6 Flashcards
defined as the range of engine operation where the power lever controls the fuel schedule and the blade angle of the propeller
Beta Mode
defined as the range of engine operation where the propeller lever controls the propeller speed through the constant speed governor and the power lever controls only the fuel schedule through the fuel control unit (FCU)
Alpha Mode
What condition is the primary propeller governor in during Beta mode?
Underspeed
What happens if the primary governor fails to control the propeller in an overspeed condition on a PT6 engine?
The overspeed governor will control the oil flow from the propeller hub back to the gear reduction section
When the engine enters the Alpha mode of operation How is the walking beam and Beta valve prevented from making further pitch changes to the propeller?
The cambox enter the constant radius slot and no further movement of the reversing cam and teleflex cable is permitted
On an aircraft equipped with a PT6 engine and Hartzell propeller combination What drives the propeller?
Exhaust gasses drive the free turbine connected to an output shaft in the power section which is connected to a gear reduction assembly which drives the propeller
How is propeller pitch controlled in Beta mode on a PT6 engine?
Propeller pitch is controlled by the power lever in the flight deck in Beta mode by controlling the oil flow to the propeller hub through the Beta valve.
