Yeoman Cropmaster YA-1 250R, VH-ABH, Murrinindi, near Yea, Vic, 21 March 1970

The pilot was carrying out aerial spreading operations in hilly terrain using a left hand racetrack pattern. The superphosphate was being spread on both the straight sides of the pattern working inwards. As the pattern became narrower it became necessary to carry out a procedure turn at the end of each run. At the end of the second run during his eighteenth flight for the day, the pilot was carrying out a procedure turn in a blind gully. The area where the turn was made was such as to take the aircraft over progressively rising terrain during the turn because of the ridge structure. The aircraft was approximately half way around the turn when the pilot noticed his airspeed was 70 knots instead of his anticipated 90 knots. He lowered some flap, decreased the rate of turn and, as the aircraft appeared to sink, he operated the dump lever to jettison the remainder of his load. While still in the left turn the aircraft struck trees on a small ridge within the gully. The pilot closed the throttle, pulled back on the stick, and the aircraft sheared through several trees before falling inverted to the ground 240 feet beyond the first point of impact with the trees.