Amateur-built BD-4 accident near Brookfield, Wisconsin, January 4, 2017

The NTSB's narrative final · quoted from the NTSB record

The private pilot was departing from runway 21 for a cross-country flight; the windsock indicated a 15 kt or greater right crosswind. A nearby weather station reported wind from 280° at 20 kts gusting to 28 kts about the time of the accident. The rear seat passenger reported that, during the takeoff roll, the airplane became airborne twice and the pilot applied right rudder to return to the runway centerline. The airplane then continued left over the grass next to the runway and travelled several hundred feet before impacting a sport utility vehicle (SUV) parked in an aircraft tie-down area about 250 ft from the runway 21 centerline. The passenger reported that, before impact, the pilot was "vigorously pumping the rudders back and forth (left and right)." A witness reported that he could not see the airplane when it started its takeoff, but when it came into view, the airplane appeared to be "having difficulty." The nose was slightly up, and the right wing was down, and the tail was "oscillating." Examination of the accident site revealed skid marks on the runway and tire tracks in the grass leading to the main wreckage. The total distance from the beginning of the skid marks on the runway to the SUV was 953 ft. The skid marks showed that the airplane veered to the left, departed the runway, and momentarily became airborne twice before settling back to the ground, then continuing another 262 ft to impact the SUV. A postaccident examination of the airplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Given the lack of mechanical anomalies and the wind conditions present at the time of the takeoff, the accident is consistent with a loss of control during takeoff in crosswind conditions.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.