TOKYO, Sept. 7 (Xinhua) -- Japan's Maritime Self-Defense Force (MSDF) said on Thursday that a recent helicopter crash off northeastern Japan was caused by human error, and flights of helicopters of the same type will be resumed.
Three of the four crewmen aboard the helicopter were still missing and the MSDF is continuing searching for them.
A SH-60J patrol helicopter belonging to the MSDF lost contact during a landing and takeoff drill on a destroyer off Aomori Prefecture, northeastern Japan on Aug. 26.
Four people were on board the helicopter. One of them was rescued some 40 minutes after the incident, while the other three remained missing.
Part of the wreckage of the helicopter was found later around the crash area. The water at the crash site is about 2,600 meters deep.
According to the MSDF, based on data from the flight recorder and the account of a rescued crew member, the crash happened when the crew members were focusing on fixing an error with the bearing indicator and failed to notice the chopper was losing balance.
It said that the chopper took off from the destroyer Setogiri at 10:33 p.m. that night during a night landing and takeoff drill, but soon a warning light suggested that there was a problem with the bearing indicator.
While the crew members were busy fixing the indicator, the chopper became unstable and soon lost its balance and plunged into the sea, and the crew failed to notice it in time.
As there is "no problem with the helicopter itself," the MSDF said that it will resume flights of choppers of the same type which have been grounded following the accident.
The incident happened just 10 days after a MSDF CH101 helicopter flipped over at the Iwakuni Air Base in Yamaguchi prefecture on Aug. 17, leaving four people on board injured.
Shingo Mimura, governor of Aomori prefecture, has said that the crash was "extremely regrettable" and could increase public distrust in the safety management of the SDF.