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Aviation History
1985
1985 - 2478.PDF
AIR TRANSPORT JAL 747 fin detached TOKYO The vertical stabiliser of the Japan Air Lines Boeing 747SR, which crashed killing 520 people, was severely damaged before the aircraft hit the ground. That much can be said with certainty. The investigating Japanese authorities have gone further. On August 15, three days after the accident, the Airworthiness Division of the Japan Civil Aviation Board said: "Circumstances seem to indicate that the damage to the vertical stabiliser and rudders might be the starting point of the accident". The statement followed the recovery of parts of the 747's vertical stabiliser, lower rudder, and of the duct from the auxiliary power unit and panelling from the rear fuse lage in Sagami Bay, about 95 miles from the crash site in the mountainous Gamma prefecture north-west of Tokyo. Other parts of the tail fin and horizontal stabilisers were discovered detached at the crash site. Boeing said about 50-60 per cent of the fin remained attached to the fuselage. The board ordered inspections to begin on all 69 Boeing 747s registered in Japan, of all marques. The inspections were to concen trate on the vertical stabiliser and rudder. Those 747s with more than 15,000 cycles must be checked within 100 flying hours, the board said. Aircraft with fewer than 15,000 cycles had to be checked within 300 flying hours. The 747SR which crashed (JA8119) had flown 25,025hr and 18,830 cycles since entering service with JAL in 1974. Boeing says the highest cycle 747 in service has flown 22,970 cycles. It is operated by a Far Eastern carrier. The highest hour 747 has 62,698hr. The world fleet totals 17 million hr. The directive ordering the inspection specified the following areas. On the verti cal stabiliser: the auxiliary spar link assembly, attach ment fitting, and their adja cent structures; fin to fuselage Part of the wreckage from the JAL 747SR which crashed north of Tokyo on August 12, killing 520 people attachment between the front spar and rear spar, rear surface to front spar and front surface to rear spar; front spar to fuselage attachment and rear spar to fuselage attach ment. In the rudder area the inspection will cover: support hinges of the upper and lower rudders, the balance weights of the upper rudder (inspection for mounting conditions); rudder power control package (inspection for hydraulic fluid leakage and Play). JAL estimates that these checks will take about 6hr for each aircraft, and exam ination of its whole 48-strong 747 fleet will take up to 20 days. The airline operates 14 747s with more than 15,000 cycles. Japan Asia Airways, part owned by JAL, operates two 747s with more than 15,000 cycles. Boeing issued a telex at the end of last week drawing 747 operators' attention to the Japanese directive and added that, in the light of the reported decompression of the aircraft, operators may wish to inspect the after-portion of the pressure hull. The US Federal Aviation Administration said it had recorded 11 instances of structural defects in tail sections over the past five years. Ten involved cracks, sheared bolts, and corrosion in components related to the horizontal stabiliser. The FAA received 16 further reports of problems with flight control com ponents in the 747 tail sections in the past five years. Of these, six involved cracks in elevator control rods and seven hydraulic system prob lems. Despite the Japanese concentration on the 747's tailplane, other causes have not yet been rejected. Shortly after the crash, two terrorist groups in Japan claimed responsibility. A JAL spokes man said: "Terrorism has not officially been ruled out, although it is not considered likely." However, the discovery at the crash site of the starboard service door to the passenger cabin (R5) intact has killed early speculation that damage to the tail fin was caused by this door flying off. About 14min before the aircraft disappeared from radar screens the pilot reported that the door was broken. Flight JL 123 from Tokyo to Osaka took off from Haneda Airport at 18.12 (local time), four minutes late, for the hour-long journey. At 18.25 the pilot reported that he had an emergency and descend from 22,500ft to 19,500ft. Two minutes later he requested radar guidance and almost immediately, reported that he was unable to control the aircraft. The 747 was now flying inland, north wards instead of westwards along the planned flight path.. At 18.31 controllers at Nagoya asked whether the pilot wanted to land there, but •- he asked to return to Haneda. At 18.41 he reported the prob lem with R5. The aircraft was now descending rapidly. Five minutes later the pilot reported that he was unable to control the aircraft. He asked. for guidance from Haneda. At 18.54 he repeated that he had lost control and said he did not know his position. He was told he could make an emergency landing at Yokota USAF Base. There was no reply. At 18.57 the aircraft disappeared from radar screens at 9,500ft. The aircraft crashed on a forested mountainside about 70 miles north of Tokyo shortly afterwards. The spread of the wreckage indi cated that it had hit the ground three times before coming to rest. An eyewitness account from one of the four survivors, all of whom were sitting in row 56 towards the rear of the aircraft, is helping the investigators piece together the evidence. Off-duty stewardess Yumi.**^ Ochiai said that at about 18.25, 13min after take off, there was a loud bang from above the passenger cabin, I FLIGHT International, 24 August 1985 • I
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