Required Equipment ???
I have never held a US ATPL or flown any jet smaller than a 737 so I am not so familiar with bizjets under US regulations....... Stop me if I get this wrong!
This CJ3 would have been operating under FAR Part 23 with a single pilot permitted by the MTOW being less that 12,500lbs and less than 10 passenger seats. Did I get that right?
FAR Part 23.1457 appears to require a cockpit voice recorder with the functionality described in Part 23.2500 ? Furthermore I don't believe this aircraft would be permitted to operate with a single pilot under any other worldwide jurisdiction (other than those few states that have decided to adopt FAA rules).
BTW.... That's not a question for the engineers !