An important issue to be looked at is not the PIC. It is operational control.
Who had operational control over the days operations - the ferry flight to deliver pilots and the subsequent flights - both of the accident flight and of the other flight.
Everyone debating this accident should read the report into the Citation that ended up on the motorway at Southampton some years back.
The major issue in that was not who was the handling pilot it was not who was pilot in command - it was the person who effectively had operational control and their (knowing or unknowing) application of peer (junior to senior pilot but opposite in management terms) pressure............without having to utter a word.
If you know you are going to be rewarded for doing something or if you know that you are going to loose out by not doing something then there is a lot of pressure on you to do whatever that is. The person who delivers the reward or not as the case may be has effective control (operational control) of the situation............as soon as they make the prize available.
Regards,
DFC