The pilot seems to be at fault but he had the plane at an unnatural angle
It may well be that the planes unatural angle was caused by it losing part of its wing after contact with a radar antenna before it hit the trees...
The shape of an aircrafts wings are designed to generate lift as the air flows over them , thats what keeps it in the air , and if you get a situation where one of those wings suddenly becomes a bit smaller , perhaps due to hitting a radar antenna and losing a portion of wing . you will get a whole lot less lift on that wing...
The first thing that happens is that wing will drop as it loses lift , and in many cases the aircraft will roll over and go into a spin...
If you have enough height , and you have not lost too much wing , you can compensate the loss of lift on that wing , by use of the controls , but this aircraft was already way too low , and the dipped wing just made it even more impossible to keep clear of the looming trees...It may be it had lost enough wing to be certain to crash anyway , but further contacts with the trees made a crash certain...Hitting the trees with one wing dipped would have sent the aircraft cartwheeling into the ground...there was no chance of any survivors....