STC for Pilatus PC–12

Dubbed ”the Silent 7” because of its seven blades and resultant noise reduction capabilities, the manufacturer said this propeller increases the overall operational capabilities of Pilatus’ PC–12 series. It reduces ground roll and takeoff distances by 10 and 15 percent, respectively; improves climb performance; increases ground clearance to avoid foreign object debris; and reduces cabin noise (by up to 7 A-weighted decibels) compared to the original, metal propeller. The company noted that the aircraft noise level is reduced by 4 dB(A) in order to comply with European airport noise protection ordinances, allowing the aircraft unrestricted operations in those countries.

The blades are made of a natural composite and are protected from erosion by a nickel alloy on their leading edges. Blade damage through foreign object debris can be repaired, and the manufacturer guarantees unlimited blade life. No engine modifications are necessary, and the company maintains that the propeller provides almost vibration-free operation.

According to MT Propeller, this is the “world’s first 7-bladed propeller certification.” The manufacturer was founded in 1981 by Gerd Muehlbauer and is headquartered in Germany, with a U.S. service center in DeLand, Florida. The company manufactures two-blade to seven-blade hydraulically controlled variable pitch propellers for engines producing up to 5,000 horsepower, flying approximately an accumulated 180 million hours, according to its website.