TOKYO — Lack of instructions to the crew and their failure to keep a lookout and communicate led two Japanese navy helicopters to collide during training, killing all eight people on board, a Japanese navy report said Tuesday.
The two SH-60K reconnaissance helicopters from the Maritime Self-Defense Force crashed in April during nighttime anti-submarine training near Torishima island, about 600 kilometers (370 miles) south of Tokyo while flying to the same mock target to detect a submarine.
Just before the collision, the two helicopters — while flying at different locations — headed to the same target based on a scenario of a submarine being detected, according to the Maritime Staff Office investigation report. They were under the control of two separate ship-based officers who were giving instructions to the two aircraft, the report added.
The absence of collision avoidance maneuvers on either side indicates both helicopters miscalculated the distance between them, the report said. Then the nose of the helicopter flying straight ahead collided with the left side of the other one that was turning clockwise at the same altitude, the report said.
It noted that crewmembers failed to keep an adequate lookout or share information, while their two commanding officers were also not communicating with their crew or giving appropriate instructions to each helicopter, for instance, to fly at different altitudes.
In the report, the MSO said it is necessary to ensure adequate lookout by crewmembers, upgrading of equipment such as installing a proximity warning system, and requirement of adequate communication between officers in charge.
“We take seriously the investigation results of the accident that took eight people's lives and do everything we can to take preventive steps, with a determination not to have any more casualty,” Defense Minister Minoru Kihara told a news conference.
Kihara said flight training involving multiple SH-60Ks was to resume on Tuesday. The helicopter training had been restricted to solo flights since the crash.
The crash came as Japan, under its 2022 security strategy, decided to accelerate its military buildup and fortify its defenses on southwestern Japanese islands to counter China's increasingly assertive military activity.
Tokyo has rapidly expanded naval exercises and joint drills with the United States and other partners in recent years.
The twin-engine, multi-mission helicopters developed by Sikorsky and known as Seahawks were modified and produced in Japan by Mitsubishi Heavy Industries. The report said there was no mechanical issue involved in the accident. Japan has about 70 of them.
