How many hours did the PIC have? Who trained him? Was he trained in basic instrument flying?
Seems the holes on the Swiss cheese lined up on that night BUT the PIC is the last line of defense to close the holes in the Cheese and it seems he either didn't know how or wasn't trained to.
A situation he most likely shouldn't have gotten himself into in the first place.
When an Airline accident happens the investigators look at all contributing factors including the actions of the crew themselves, the training of the crew and the operator. Just as in QF10 BKK over run.
Had the PIC flown through this area before? Was he familiar with the area?
Why did he turn toward the hills at night not knowing if he could maintain VFR?? ( I'm assuming he was NVFR? )
I fly into some pretty crappy places around Asia and I sure a sh** ain't going to put my aircraft in harms way because ATC won't cooperate. I'll declare a PAN or a MAYDAY if I have to.
Edit----seems his DG failed later on? So obviously he didn't intend to fly over the mountains?