I've got about 800 hours in the PC-12, so here's my take...
There's no belted lav in a PC-12. The lav is at the top of the air stair door and you can't put anybody in there unless the doors are open, blocking off the cabin and the cockpit.
Most PC-12s are set up for 6 passenger seats in back. Some are set up for 8. You can have as many as 9 in a commuter configuration.
The PC-12 has a stick shaker and a stick pusher. On each wing there's an AOA vane which goes to a computer. Either computer can command a shake, both computers have to agree to command a push. There is also a "Pusher Ice Mode", where the AOA that a push is commanded is reduced by 8 degrees. So if it would normally push at an AOA of 12, in Ice Mode, it would push at AOA of 4.
If they were in icing conditions, they would have had the prop de-ice on as well as the inertial seperator open. This condition puts the pusher into Ice Mode.
AOA on the PC-12 is displayed on the left side of the EADI like this:
F
<>
O
<>
S
The O represents 1.3 Vso. The top diamond shows that you're fast, the bottom shows that you're slow. There's a pointer that shows where you're at.
When they crashed, they were in a gear down, flaps up configuration. In this configuration, 1.3 Vso (the donut) is about 108 KIAS when the pusher is operating normally. When the pusher is in ice mode, 1.3 Vso jumps to 134 KIAS.
The "nose down" that was reported by witnesses would be consistent with getting a stick pusher.
There may have been 14 souls on board, and while it's not legal by any means, the plane should have been able to handle the load. But, you've got to understand the systems of the plane and how they work. By simply turning off the prop de-ice, you gain a huge cushion of airspeed. When I flew the PC-12, I'd typically turn off the prop de-ice at the FAF, especially on a circling approach, to take it out of pusher ice mode.
