1 Dead, 5 Hurt in California Military Copter Crash Investigators seeking cause By Mary Papenfuss, Newser User Posted Jul 7, 2011 3:37 AM CDT 0 comments Comments A Marine rescue boat takes off earlier this year in another rescue after an amphibious assault vehicle sank in a harbor at Camp Pendleton. Now a Marine has died in a Pendleton helicopter crash. (AP Photo/KGTV/10 News.com) (Newser) – A Marine was killed and 5 others injured when a helicopter went down during a training exercise at Camp Pendleton in San Diego County. It wasn't immediately clear how serious the injuries were, but all were being treated at local hospitals, reports AP. Investigators are seeking the cause of the crash of the "Yankee Huey" helicopter. The UH-1Y craft is an updated version of an earlier model that boasts "crashworthy" crew seats.