James Stright, who was known to family members as J.R., was killed in the helicopter accident that also injured eight other service members, the Billings Gazette reports.
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The exercise was reportedly done to help soldiers practice boarding, searching and seizing ships that may be under the control of pirates or terrorists.
Jerilyn Stright, the sergeant's mother, told the Gazette that her son was known for his humor and smile, and that he liked to hunt and fish after school.
"His entire adult life was dedicated almost exclusively to the military," Jerilyn said. "He existed for it."