Five crew members who were aboard two U.S. Marine Corps combat planes that collided in midair off the coast of Japan last week have been declared dead, the Associated Press reports. Two crew members were rescued after the incident, but one died Friday. The sole surviving crew member is reportedly in stable condition after being rescued by Japanese military personnel. Military officials have not yet released the crew members’ identities, saying only that they were based at the Iwakuni air station near Hiroshima. The five-day search began after a KC-130 refueling tanker and an F/A-18 fighter jet plowed into one another Thursday. An investigation into the crash is still underway. The incident comes after a string of accidents involving U.S. military aircraft. A KC-130T plane crash that killed 15 Marines last summer was considered the deadliest of those accidents, according to findings of a Marine Corps investigation released last week. The findings reportedly showed the Air Force had allowed a “deteriorating propeller blade” on the aircraft to go unfixed prior to takeoff.