DISASTER FLIGHT JAPAN 747SR

The Boeing 747SR (Short Range) is an aircraft that was designed to be used on short, high-density routes. Due to its lower fuel capacity, it is capable of carrying over 550 passengers. For Japan Airlines 747SR, JA8119, Monday August 12, 1985 began no different than any other day. The aircraft had previously flown in from Kyushu and had arrived back at Haneda, Tokyo at 5:17 p.m. The aircraft was refuelled and new flight crew boarded, while the cabin crew remained from the previous flight. The only anamoly on this flight was that the First Officer was being upgraded by a Check Captain for promotion himself to Captain. JAL123, which was the assigned flight number for this trip, taxiied away from the gate at 6:04pm with 509 passengers on board, ready for the flight to the industrial city of Osaka which was 400km away.

In command of this flight was Captain Masami Takahama, 49, who was a Training Captain and had been with the company for nineteen years. He had 12,500 hours of total flight time. The flight took off at 6:12pm, and five minutes later while climbing on track to FL240 in visual conditions asked Tokyo ATC for a more direct route to Osaka. Tokyo Approved this request. Six minutes later as Tokyo ATC was tracking the flight, the emergency transponder code appeared on their screen, which was 7700. This is the emergency sqawk for aircraft in distress.

Aircraft: " Tokyo, Japan Air 123 . Request immediate... ah... trouble. Request return back to Haneda... descend and maintain flight level two two zero."

Controller: "Roger approved as you requested!"

Aircraft: "Radar vector to Oshima please"

Controller: "Turn right, heading 090, radar vector to Oshima."

The actual route of Japan Air 123 during the accident. Click for larger view.

The controller noticed that instead of making the 177° turn back toward Oshima Island, the aircraft was making only a gradual turn to the right onto a course of 50°. Crossing the Izu Peninsula and leaving it astern, it then headed out over Suruga Bay in a north-westerly direction. The aircraft had suffered an explosive decompression of its rear vertical tail plane, losing a 15 foot section of the leading edge and having all its flying controls rendered useless.

The aircraft impacted the lower slopes of Mount Osutaka, killing all but four people on board. The cause was found to be an improperly repaired rear pressure bulkhead, which had been repaired by Boeing some years before after the aircraft had been involved in a tail scrape on landing. This caused the loss of the flying surfaces in the tail, and the control surfaces to a certain extent on the wings. This was and still is the worlds worst accident involving a single airliner.

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