An2 tanks full, cabin full means to much aft cg.
Plane will lift off in stall and crash.
Often happens with parachute jumpers.
You have to leave the last seat empty and sit this jumper on the cockpit step.
edit: Just found there were only 4 people on board.
So I take back my comment
Edit 2
https://www.baaa-acro.com/crash/cras...guska-1-killed
Wrong trim tab offset