 The investigation was unable to determine conclusively what had caused the horizontal stabilizer trim to be set improperly, but theorized that the most likely cause was an aircraft system malfunction.On 21 July 2008, a United States Air Force (USAF) B-52H Stratofortress crashed into the Pacific Ocean approximately northwest of Apra Harbor, Guam, after taking off from Andersen Air Force Base.The aircraft, named "Louisiana Fire" and with the mission call sign of "RAIDR 21", was about to participate in a flyover for the Liberation Day parade in Hagåtña.