The fatal June 1995 crash off Sagami Bay of an antimine helicopter belonging to the Maritime Self-Defense Force was caused by a mechanical malfunction in the rotor controls, MSDF officials said Friday in its final report on the case.
The helicopter, manned by a crew of eight that was killed in the accident, was participating in minesweeping drills June 6, 1995, with another aircraft over the bay shortly after taking off from Shimofusa Airfield in Chiba Prefecture at around 10 a.m.
At around 11:30 a.m., while flying at an altitude of about 50 meters, a fire broke out in the center of the aircraft. The crew radioed an emergency message before ditching.
In the findings announced Friday, MSDF officials said that although the MSDF failed to obtain physical evidence of the crash and broke off its initial investigation at the time, a similar accident in the United States the following year led them to ask the manufacturer of the helicopter to investigate its controls.
The helicopter is an MH-53E manufactured by Sikorsky Aircraft Corp., and is the largest type in the MSDF. In May 1996, a CH-53E helicopter, also made by Sikorsky and similar to the MH-53E, crashed in the U.S. because of heat damage caused by a swash plate controlling the main rotor.
Following the incident, the MSDF had Sikorsky investigate the case, leading it to decide that a similar type of damage affected the controls of the MH-53E.