exercise, the c-2 navy propeller plane ditched into the philippine sea, as it made its way towards the aircraft carrier the "uss ronald reagan." it was about 500 miles off the coast of okinawa. the navy says that within minutes, eight personnel were plucked from the sea in good condition. but a huge search involving the "reagan" and multiple air craft continues tonight. >> the fact that we had so many people survive this mishap suggests that this was a deliberate act. that it was a ditching, that there was some mechanical problem. >> reporter: this is the sixth major incident involving the 7th fleet this year. two previous collisions between navy destroyers and merchant ships caused the deaths of 17 sailors. the captains of those ships and the commander of the 7th fleet, vice admiral joseph aucoin, have been relieved of command because of the incidents. now, the japanese defense ministry, tom, is saying that engine failure might have brought that plane down. but the u.s. navy is only saying it is investigating the crash. tom? >> and the search still under way tonight.