CEN13LA426

The pilot reported that he had completed three uneventful aerial application flights on the day of the accident; however, shortly after lifting off for the fourth flight, the airplane encountered a sudden wind shear and was unable to climb out of ground effect. The airplane descended from an altitude of 10-12 feet above the ground into the corn crop located off the end of runway. The pilot reported no preaccident mechanical malfunctions or failures that would have precluded normal operation. A review of available wind data indicated that calm wind conditions prevailed throughout the morning; however, a shift to a northwest wind occurred about the time of the accident, which would have resulted in a tailwind and a reduced climb gradient.

On July 20, 2013, at 0945 central daylight time, an Air Tractor model AT-502 airplane, N502MH, was substantially damaged when it impacted terrain shortly after takeoff at Sneek Airport (2IL0), Shannon, Illinois. The airline transport pilot was not injured. The airplane was registered to TW Air LLC and operated by Woodley Aerial Spray Inc., under the provisions of 14 Code of Federal Regulations Part 137, without a flight plan. Day visual meteorological conditions prevailed for the local aerial application flight that was departing at the time of the accident. The pilot reported that he had flown three uneventful aerial application flights earlier that morning in the accident airplane. After lifting off on the accident flight, the airplane encountered a sudden gust and was unable to maintain a climb outside of ground effect. The airplane descended from an altitude of 10-12 feet above the ground into the corn crop located off the end of runway 18 (2,640 feet by 125 feet, turf). The right main landing gear collapsed during the landing. The airplane came to rest upright and the pilot extracted himself from the airplane uninjured. The aft fuselage and wings were substantially damaged during accident impact sequence. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The nearest aviation weather reporting station was located at Albertus Airport (KFEP), Freeport, Illinois, about 6.5 miles northeast of the accident site. At 0935, the KFEP automated surface observing system reported the following weather conditions: wind 320 degrees true at 3 knots, visibility 10 miles, sky clear, temperature 26 degrees Celsius, dew point 19 degrees Celsius, altimeter setting 29.95 inches of mercury. A postaccident meteorological review of available wind data indicated that calm wind conditions prevailed throughout the morning; however, at 0935, the wind was from the northwest at 3 knots.