引用・参考資料等 https://www.quora.com/How-do-helicopters-land-on-water-If-they-can-how-do-they-keep-from-sinking-into-the-ocean-floor-while-landing-or-taking-off-againhttps://caspir.warplane.com/asrc/acn/200000416/https://www.quora.com/unanswered/Can-you-land-a-helicopter-on-water-If-so-how-deep-can-it-go-before-it-sinks
http://www.nicovideo.jp/watch/sm44090368
