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 |
| idle | 79 | 75 | 73 | 70 |
| taxi | 74 | 72 | 70 | |
| takeoff | 82 | 82 | ||
| climb | 84 | 82 | ||
| 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 |
My rich friend’s solution to this problem was simple: when he ordered his, he simply asked lemo sockets to be installed for every seat to power Bose A20 headsets for all passengers.
Hooked up to the intercom, he can talk with them or isolate the crew from their chatter.
Actually, there are lemo sockets in ‘just’ the front four passenger seats (using a 4 place lemo capable intercom, interfaced with the audio panel up front as Bas has already indicated). Also, the headsets are actually older Bose headsets that I used to use in the Cirrus that I traded in on the PC-12.
This was also done as a retro-fit – not as a build-time option – so its certainly something that is possible to add in ‘later’ on other ships too. We really like it.
I use those headsets when I have other pilots on board, so they can be a part of the process and the flight. That works really well for them and for me – pilots generally love this (and perhaps especially non-IFR rated pilots who get to gain an appreciation of the procedural/radio aspects of an IFR flight).
For non-pilots we generally fall back to the Bose QC15’s that are shoe-horned into the lifejacket tray under each passenger seat, for cabin noise reduction.
We are currently sorting out the engineering service order to plumb cockpit audio (output only, and with a cutoff switch) into the 3.5mm sockets that are pre-installed into each seat position at build time, connected (at present) to a CD player that we never use (in this era of music-playing smartphones in every pocket).
This means passengers who are curious to listen to pilot/ATC/radio chatter will be able do so on the QC15’s without being able to talk back to the cockpit (which can be an issue if non-pilots in the back start to chat amongst themselves while wearing the Bose headsets).
I do wish the QC15’s had some form of auto-power-off, however, as I do keep going through AAA batteries due to people leaving the QC15’s on after they deplane.
Regards,
Bas’s abovementioned rich friend 🙂