These measurements were made in Pilatus PC-12 s/n 353, a Series 9 airplane with 10,700 hours. Note that these show that the plane is at least 2 dB quieter than an almost-new PC-12 NG (previous posting).
Measurements were made with a 10-year-old Radio Shack digital sound level meter, model 33-2055, set to “slow” and “A-weighting”. Measurements were made with the meter’s microphone near the ear level of a person seated in the PC-12. All speeds are indicated airspeed (i.e., true airspeed and ground speed would be higher).
|Phase||Pilot||Row 1||Row 2||Row 3|
|6500′; 180 knots||88||82||80||79|
|7000′; 215 knots||88||87-88||85||84|
|10,000′; 208 knots||88||87||85||84|
|13,000′; 203 knots||87||86||85||83-84|
|15,000′; 204 knots||88||87||85||83|
|FL280; 170 knots||86||83||82||81|
|FL280; 128 knots||85||78||77||75-78|