The album is based on the crash of Japan Airlines Flight 123 on the evening of 12 August 1985. Twelve minutes into its flight, the Boeing 747 suffered an explosive decompression due to failure of its rear pressure bulkhead, caused by a faulty repair 7 years earlier. The explosion tore off most of the aircraft's vertical stabilizer and ruptured all four of the hydraulic systems, causing the loss of all flight control surfaces and rendering the aircraft uncontrollable. The pilots fought to keep the aircraft aloft for nearly 32 minutes, but eventually became trapped in the towering mountain ranges surrounding Mount Fuji and crashed, killing 520 out of the 524 passengers and crew on board. It remains the deadliest single-aircraft disaster in history. Some pressings of the album contain a recording of the last 30 seconds of the flight as an easter egg hidden in the pregap.