The Lockerbie Bombing of a Pan American 747-100 occurred in December 1988 . Pan American was ultimately found liable for negligent security practices directly contributing to the Lockerbie Bombing . The explosion of Pan Am Flight 103 at Lockerbie in December 1988 is widely regarded as the ' final straw ' in the ability of Pan American to remain a going concern . Pan Am was a pioneer of aviation , a premier American brand and was considered the de facto flag carrier of the United States before going out of business on December 4 , 1991
Pan Am Flight 103
Pan Am Flight 103
Ed Acker