A Maritime Self-Defense Force helicopter flipped during a drill Thursday at Iwakuni Air Base in Iwakuni, Yamaguchi Prefecture, leaving three servicemen hurt and another unwell, the MSDF said.

The CH-101 chopper overturned at the MSDF base while descending during a drill for hauling cargo suspended from the aircraft, the MSDF said.

Four of the eight men aboard were taken to a hospital after the 2:20 p.m. accident. Three had light injuries but another complained of feeling ill.

The MSDF said a CH-101 assigned to the Japanese icebreaker Shirase for an Antarctic expedition was on a training flight when it flipped over on its side, damaging its main rotor.

According to the MSDF website, the multipurpose CH-101 is 22.8 meters long, 18.6 meters wide and generally flown by a crew of four, though that can rise depending on the mission.

The base is adjacent to U.S. Marine Corps Air Station Iwakuni, and its runway is jointly used by the MSDF and the U.S. Air Force. The base also conducts commercial aviation operations as Iwakuni Kintaikyo Airport.