What was found
ACFT ENGAGED IN AGRICULTURAL OPS. AFTER A PASS ON A FIELD, PILOT ATTEMPTED TO CLOSE HOPPER DOOR WITH DRY RELEASE HANDLE. HANDLE BROKE AT ONE HINGE PIVOT POINT RENDERING HANDLE INPUT INOPERATIVE. DUST CONTINUED TO EXIT HOPPER AND PILOT DID NOT WANT TO DISCHARGE DUST OVER THE DIRECTION ACFT WAS GOING AND DECIDED TO CIRCLE BACK TO AN AVAILABLE LANDING LOCATION. PILOT TURNED ACFT, APPARENTLY FLEW THROUGH DUST FLOATING IN AIR AND THE DUST IGNITED AND THE FIRE FOLLOWED ACFT. BEFORE TOUCHDOWN, FLAMES APPROACHED HOPPER. ACFT LANDED AND ROLLED ON TO A GRASS SURFACE, FLIPPED AND BECAME ENGULFED IN FLAMES.