Piper PA-25-235 Pawnee, VH-OMA, 15 km north-west of Tumby Bay, South Australia, on 21 June 1990

Circumstances:

The aircraft was engaged in the final stages of a pasture spraying operation. The area of operation was a small field surrounded by trees. A powerline was located beyond the trees at the southern end of the field. After committing the aircraft to a low-level pass towards the south, the pilot remembered the partially concealed powerline but was unsure of its exact position. When the powerline became visible against the skyline, the pilot realised that he would be unable to pull up over it and elected to fly through the treetops beneath the powerline. Right wing impact with the trees caused the aircraft to yaw and the rudder to strike the powerline as the aircraft passed beneath it. Despite right wing and rudder damage, the pilot retained control and landed the aircraft in the adjacent paddock where he evacuated the aircraft without assistance or injury. Examination of the aircraft determined that there were no pre-existing mechanical defects, abnormalities or damage which can be considered as factors in, or contributory to, this accident. The pilot acknowledged that he did not conduct a specific check of powerline positions before commencing the clean-up run. The pilot had re-commenced agricultural flying, three weeks prior to the accident, after approximately 9 months of fish spotting operations.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The Pilot-in-command failed to conduct a "Supplementary Wire Hazard Check" prior to commencing the clean-up run.

2. The Pilot-in-command lacked recent calendar experience in agricultural operations and below obstruction height flying. 

Recommendations:

1. That the Civil Aviation Authority give consideration to reducing the calendar period nominated in Civil Aviation Orders section 40.6 para 11, "Recent Experience Requirements", from 12 months to 90 days.

2. That the Civil Aviation Authority specify a syllabus for, and the qualification of the person conducting, agricultural proficiency checks in accordance with Civil Aviation Order 40.6.