As this tragic accident occurred in Scotland, it will not be the CPS who decide whether to prosecute. The Crown Office and McNacker will run the show. Although historically the CAA have brought prosecutions for breaches of the ANO etc.
I had to attend, as a witness, a fatal accident inquiry in Dumfries in 1993 (AAIB REPORT had been published) as a result of one of our BAeFC Gulf Air solo student crashing near Sanquhar.
Transcripts derived from ATC tapes were produced as part of establishing the facts ~ time lines.
So FDR/CVR evidence ~ this will be produced at the fatal accident inquiry post any other proceeding.