Primary finding
Probable cause
The pilot's failure to maintain directional control during an aborted takeoff.
Investigator assessment
Analysis narrative
The pilot was attempting to take off for an agricultural application flight with the airplane loaded near gross weight. During the takeoff roll, the pilot thought that the airplane would not attain flight. The pilot aborted the takeoff about halfway down the runway without dumping the load of agricultural applicant. With about 400 feet of runway remaining, the pilot applied reverse thrust, and the airplane ground looped. Examination of the airplane revealed no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.
Source record
Factual narrative
On June 4, 2012, about 0930 central daylight time, an Air Tractor Inc AT-401, N4547Q, impacted terrain during an aborted takeoff on runway 26 at Kenmare Municipal Airport (7K5), Kenmare, North Dakota. The pilot aborted the takeoff after he thought the airplane performance was degraded, and the airplane ground looped. The commercial pilot was uninjured. The airplane sustained substantial damage to the right wing. The airplane was registered to the pilot and operated by Northern Ag Service under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed and a flight plan had not been filed. The local flight was originating at the time of the accident. The pilot stated that the purpose of the flight was to spray fungicide on winter wheat. The pilot reported that the airplane weight was 7,723.5 pounds and the maximum gross weight of the airplane was 8,000 pounds. During the takeoff roll on runway 26 (3,700 feet by 60 feet, dry asphalt), he made the decision to abort the takeoff when the airplane was about half down the runway, or about 1,900 feet down the runway. The engine instrument indications of 96 percent torque and 645 degrees inter-turbine temperature "looked ok." He said that he made the decision to abort the takeoff because the airplane "did not feel like it was going to fly." As the airplane slowed and about three-quarters down the runway, or about 2,775 feet down the runway, he placed the engine power lever in reverse. The airplane ground looped 180 degrees. The pilot stated that if he had dumped the fungicide, he could have possibly avoided the accident. According to a Federal Aviation inspector, examination of the airplane revealed no mechanical anomalies with the airplane that would have precluded normal operation.