What happened
Following a routine takeoff from runway 2ng, the crew of the aircraft type experienced an uncommanded roll to the right while the landing gear was still extended and flaps were set to 20 degrees. The pilot attempted to maintain level flight using rudder inputs and differential thrust, noting that the rolling tendency intensified as airspeed increased. During the flight, the cockpit voice recorder captured several bank angle warnings and the pilot's instruction to declare an emergency, though no emergency checklists or memory items were initiated by the crew.
The aircraft eventually approached runway 13, where the pilot performed a landing on the right side of the runway. The aircraft touched down long and in the grass with a left quartering tailwind. After the landing, the aircraft continued to travel parallel to the runway until it struck an airport perimeter fence located beyond the runway's end. There were 0 fatalities and 0 injuries reported in the immediate sequence.
Findings
Investigation of the aircraft type revealed that the right roll spoiler was malfunctioning. During ground testing with hydraulic power, the right roll spoiler was found to remain elevated above the flush wing level, even when the yoke was manipulated. Subsequent examination at the manufacturer's facility determined that the right roll spoiler actuator had jammed, although the specific cause of the jam could not be identified through disassembly.
While the jammed spoiler initiated the roll, the crew did not perform the required memory items to mitigate the issue. Specifically, the crew failed to move the spoiler hold-down switch to the 'on' position to lock the panels down. Additionally, the aileron/spoiler disconnect T-handle was found in the pulled position. While the crew suggested this happened during evacuation, investigators found this unlikely due to the handle's design. Had the disconnect been used, it would have actually made the aircraft more difficult to control by disconnecting the left roll spoiler from the captain's controls.