Naoko no Tropic Angel: Hyouryuu

One of the first adult OVA. Released in 1985. Schoolgirl Mina and her teenage uncle Shigeru go on a trip from Los Angeles to Japan. On the plane, they meet a blonde American girl named Jenny, but soon their plane inexplicably crashes. The three become stranded together on a South Sea island. The Naoko in the title refers to the original author, not a character. This Naoko allegedly wrote this OVA's story during their own trip to Saipan when they were 17. Source: Japanese wikipedia