The pilots initially believed that a bomb had gone off inside the airplane , as this accident happened just two months after Pan Am Flight 103 was blown up over Lockerbie , Scotland . They began an emergency descent in order to reach an altitude where the air was breathable , while also performing a 180-degree left turn to fly back to Honolulu . The explosion damaged components of the on-board emergency oxygen supply system , as it was primarily located in the forward cargo sidewall area , just aft of the cargo door
Pan Am Flight 103
Pan Am Flight 103
United Airlines Flight 811