I've watched that plane come and go a lot via FlightRadar24, along with the Citation jet the institute also flies. One of the Institute's eye surgeons was onboard the plane.
Yeah, they have two CJ3's, another Cessna 340A and a Pilatus PC-12. You can hear their PC-12 N605PC handed off to Seattle Center 132.6 near the beginning of the audio clip. They reported the cloud tops at 15,000 and then the accident plane requested 15,000 and then 17,000. In the past they've operated two CJ2's and CJ1's. I believe the accident plane was their first plane, purchased in the mid 80's. They operate a chain of eye surgery and laser centers and fly the specialists in on the days they do procedures. They run a slick operation. Most of their office building are identical. I've personally seen this plane at many airports in the region over the last decade or so. I'm also very familiar with the area of the crash... very rugged terrain. A SR-22 crashed in the same area last year trying to make it to a remote vfr strip. Whatever happened, took place very quick. Possible engine(s) out + icing scenario. Very sad story.
I decided to not edit this audio as the entire 30min segment involves this plane. If you want to edit out the air... knock yourself out!