On arrival at his destination, the aircraft overflew the homestead. This was the pilot's normal practice, to indicate to persons on the ground that transport from the nearby strip was required. The aircraft was then seen apparently following a gully containing a sunflower crop in which the pilot and passenger were partners. Shortly afterwards the sounds of an impact were heard. The aircraft was found to have struck the side of the gully while in a steep nosedown attitude and probably rotating to the right. No pre-impact defect or malfunction of the aircraft was found which might have contributed to the development of the accident. However, about 12 months previously, the pilot had applied tape over the stall warning vane, thus depriving him of aural warning of an impending stall. The wreckage distribution was consistent with that which follows a stall at low level where control of the aircraft is not regained before impact. It was likely that the aircraft stalled while the pilot was manoeuvring above the crop, but the precise reason for the stall and subsequent loss of control was not established.