Proof of the PC-12 engine’s reliability is in the numbers of one of Pratt & Whitney Canada’s greatest success stories. Ranging in power from 500hp to 2,000hp, the PT6A engine family is available on more than 65 models and is in service with over 6,500 operators in over 170 countries. To-date, more than 36,000 PT6A engines have been produced for airlines, general aviation, business, agriculture, and utility markets. The specific engine type we use with PC-12s in the PlaneSense® fleet is the PT6A-67B.
The PT6A-67B features a modular engine configuration that contributes to our program’s overall efficiency. Since we can service the gas generator and power sections independent of one another, we gain great flexibility in our maintenance efforts and can better match aircraft availability with owner demand.
Within the power section of the PT6A-67B is the free-powered turbine as well as a two-stage reduction gear box which makes it easier for our pilots to stay at 1,700 RPMs and maintain the most efficient propeller speed for our model engine.
Hot gases from the gas generator expand as they move through the power turbine and drive the gears which turn the propeller shaft (e.g. free-powered turbine). A more interesting way to think about it is that the propeller on a PC-12 is actually powered by hot gases, not driven by anything mechanical.