Ist a shame i couldnt read the Accident Report, but the Cockpit Pictures brought up a Memory of the past:
I have flown the AN2 for 10yrs. in my sparetime for Sightseeing flights.
A friend of mine operated 4 of them on an AOC in Germany.
When we arrived at an Airshow often we did a Flyby with some manouevering before we landed and prepared our Sales Stand.
One day after the low pass i pulled up and turned to the right doin app. 250kmh and was greeted by Buffeting until the slat came out.
The next Thing to remember is that a Coordinated steep turn in an AN2 is "NOT" Rudder neutral. Above a moderate Bank you Need In Turn Rudder and Out of Bank Aileron to get the ball centered. This is because the AN2 has a Spiral Dive Tendency in steep turns. This amount of Aileron is already subtracted from your Roll Authority.
Also to get a bit more Rate of Roll i used sometimes a big boot of Rudder, which boosted Roll big way ( Only when playing around, not on Commercial Flights).
The Ailerons are both Sloppy and heavy. And in this Special case nobody knows how well the Accident Aircraft was maintained especially Cable Tension.