Air Tractor Inc AT 402 N1016G accident near Sac City, Iowa

Probable cause

The pilot's failure to maintain adequate clearance from power lines. Contributing to the accident was the pilot's failure to circle over the field to identify hazards before beginning the aerial application.

NTSB analysis

The commercial pilot was performing an aerial application flight to an area that a ground crewman described as a "wire farm" due to the number of power lines present. The pilot did not complete a circling pass over the target field to identify hazards before descending for the first aerial application pass. The pilot flew over a set of power lines, activated the airplane's spray function, and completed one pass to the north. The airplane then climbed and made a left turn before descending toward the west side of the target field for a pass to the south. The pilot completed a pass on the west side, then impacted power lines on the south side of the field. The airplane continued south and impacted a corn field, where it came to rest upright. The top of the vertical stabilizer and the rudder were found near the power lines.

A postaccident examination of the airplane revealed evidence of multiple wire strikes to the canopy, wire protection system, and empennage. At least one wire was deflected over the canopy, along the wire deflector cable, and cut through the vertical stabilizer and rudder. At least one wire impacted the aluminum wire protection bar and the cockpit structure consistent with the wire not deflecting over the canopy. The examination did not reveal any preimpact anomalies that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for CEN16LA292 for the full record.