**3.4 Crash of a Boeing 747 SR-100 aircraft**

A Boeing 747 SR-100 flight 123 operated by Japan Airlines crashed on August 12th, 1985 when flying from Tokyo-Haneda to Osaka [15]. In total, 520 out of 524 people on board the aircraft were killed in what is dubbed as the worst ever single aircraft accident in the history of aviation. When the aircraft was cruising at an altitude of about 24,000 ft., decompression occurred due to rupturing of the rear pressure bulkhead, causing serious damage to the rear of the plane. The airplane became uncontrollable and struck a ridge, bursting into flames. Investigations revealed that the probable reason for the initiation and propagation of fatigue cracks in the rear pressure bulkhead was attributable to improper repairs of this bulkhead and lapses in maintenance inspection.
