Poor Lookout, Altitude Control behind MSDF Helicopter Crash

The Yomiuri Shimbun
Defense Minister Minoru Kihara speaks during a press conference on Tuesday.

TOKYO (Jiji Press) — Inadequate lookout and altitude control led to the April crash of two Maritime Self-Defense Force helicopters during night training off a remote Tokyo island, an MSDF report said Tuesday.

The two SH-60K helicopters were operating under the command of different commanding officers, and coordination between them was insufficient, the accident investigation report also said.

In the accident, the No. 16 helicopter of the MSDF’s Omura air base in Nagasaki Prefecture and the No. 43 helicopter of the MSDF’s Komatsushima air base in Tokushima Prefecture collided on the night of April 20 at a point about 280 kilometers east of Torishima Island in the Izu island chain in the Pacific.

The No. 16 helicopter was commanded by the commander of the MSDF’s 4th Escort Flotilla, and the No. 43 helicopter by the captain of the MSDF destroyer Suzunami.

The accident killed one crew member and left seven others missing. All of the seven were later declared dead.

About four minutes before the collision, the two choppers were told to search for a submarine with sonar, heading for the same point from different locations.

When the No. 16 helicopter turned clockwise in an automated flight to lower its altitude and speed, it crossed the path of the No. 43 helicopter, which was flying straight ahead. The No. 43 unit then hit the left side of the No. 16 unit, the report said.

Analysis of the recovered flight recorders showed that both aircraft were aware of each other’s presence, with a No. 43 helicopter crew member reporting to the captain the distance and heading of the other helicopter two minutes before the collision.

But the two sides did not seem to care much about the approach, and neither took any evasive action until the moment of the collision, the report said.

The report pointed to such possibilities as misjudging the distance between the two helicopters at night and failing to maintain adequate lookouts as crew members were engaged in other work.

In 2001, two MSDF helicopters collided off Amamioshima Island, Kagoshima Prefecture. Following the accident, the MSDF adopted the principle of altitude separations, which requires MSDF aircraft to take different flight altitudes when they are in close proximity.

In this year’s accident, the collided helicopters were commanded by different officers, whose coordination was insufficient. The two aircraft failed to follow the principle of altitude separations, the report said.

On Tuesday, the MSDF released fresh preventive measures, including thorough lookout operations, education of crew members on nighttime visibility and automated flight trajectories, and stricter altitude control under the responsibility of the most senior commanding officers.

MSDF training flights involving multiple aircraft, suspended since the April accident, will be resumed in stages from Tuesday.

“It is extremely regrettable that we lost eight members,” Defense Minister Minoru Kihara told a news conference. “We’ll do our utmost to prevent any similar incidents from occurring with a determination to avoid any future casualties.”