One Marine was killed and 21 others required hospital treatment after their MV-22 Osprey aircraft made a "hard landing" during training in Hawaii on Sunday, the US military said.
The "mishap" was under investigation, a Marine statement said, and residents told local media they saw thick, black smoke rising from the area around Bellows Air Force Station.
"Twenty-two Marines were aboard at the time and all other 21 have been transported to local hospitals for assessment and treatment," the statement said.
The 15th Marine Expeditionary Unit departed San Diego on May 10 on a seven-month deployment.
The MV-22 Osprey is a tilt-rotor aircraft that can carry 24 Marine combat troops and combines the maneuverability of a helicopter with the speed and range of a turboprop plane.