The sailor, who is attached to the 3rd Marine Aircraft Wing, was hit by the spinning tail rotor of a UH-1Y Venom aboard Marine Corps Air Station Camp Pendleton, California around 6:10p.m. Wednesday, wing officials said.
The sailor taken to Scripps La Jolla Medical Facility by Emergency Medical Services, wing officials said, and spent several days in critical condition.
The sailor was pronounced dead just before 6a.m. Saturday, officials said.
The identity of the sailor is being withheld for 24 hours following next-of-kin notification in keeping with military protocol.
The Marines are investigating the incident.
Hope Hodge Seck can be reached at email@example.com. Follow her on Twitter at @HopeSeck.