The pilot was spraying a small paddock, to the south east of which the ground rose steeply. All spraying runs were being conducted towards the south east, with the pilot carrying out left hand orbits at the end of each run in order to reposition the aircraft. However, manoeuvring in this manner was taking the aircraft close to houses in a noise sensitive area. The pilot therefore decided to carry out a procedure turn and conduct a run into the north west. About half way around this turn the aircraft lost performance, probably as the result of a downdraft, and then stalled at about 100 feet above the ground. There was insufficient height available for the pilot to effect recovery and the aircraft struck the ground in about a 30 degree nosedown attitude. The pilot subsequently advised that he was aware that downdrafts were likely to be present in the prevailing conditions. However, he had been concerned to avoid the noise sensitive area, and had not considered the possibility of downdrafts as he manoeuvred over rising terrain. When he was attempting to recover from the stall situation, the pilot had not dumped his load because there were valuable animals in the paddock below the aircraft.
