Lack of instructions and failure to keep a lookout and communicate led to the fatal collision of two SH-60K Japanese Navy helicopters in April 2024, according to a probe report by the Japanese Navy.
The two SH-60K reconnaissance helicopters from the Maritime Self-Defense Force crashed during a nighttime anti-submarine training near Torishima island, about 600 kilometers south of Tokyo, while flying to the same mock target to detect a submarine.
According to the Maritime Staff Office (MSO) investigation report, the two helicopters headed to the same target while flying at different locations just before the collision.
The report said the helicopters were under the control of two separate ship-based officers who were giving instructions to the two aircraft.
The absence of collision avoidance maneuvers on either side indicates that both helicopters miscalculated the distance between them, the report said.
According to the report, the nose of the helicopter flying straight ahead collided with the left side of the SH-60K that was turning clockwise at the same altitude.
The report noted that the crewmembers failed to keep an adequate lookout or share information, while their two commanding officers were also not communicating with crew or giving appropriate instructions to each helicopter to fly at different altitudes.
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.
The collision killed all eight people onboard both helicopters.
“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 the Japanese press in a news conference.
Flight training involving multiple SH-60Ks resumed on July 9, 2024. Prior to that, helicopter training for the SH-60K had been restricted to solo flights after the crash.