Condolences for all aboard. These planes were built by Fuji ind under license. They came out as advanced block II, but I think they were upgraded to block III not long ago, with composite rotor blades. Way back in the 80s I was stationed at Futenma, we were supposed to have some joint exercises with JDF marines, and air cover but someone further up the food chain nixed it. They don't have a stellar record of safety. However, just as likely the plane let them down at this point.