A Marine CH-53E Super Stallion from Miramar air station in San Diego crashed near El Centro, California, on Tuesday afternoon, and all four crew members are presumed dead, the military said. El Centro is just a few miles from the U.S.-Mexico border, and the helicopter was on a training mission. The cause of the crash is under investigation, and the names of the crew members won't be released until 24 hours after their families are informed, the Miramar base said in a statement. The CH-53E Super Stallion is the U.S. military's biggest chopper, The Associated Press reports, and it has been involved in several accidents, including one last October with no injuries in Okinawa and another incident in Hawaii two years ago where 12 Marines died when two of the helicopters collided.