when was the last time two or more professional athletes (NBA, MLB, NFL) died at the same time?

(My Original Blog Post: http://www.latesttrendsguide.com/?p=3950)

it appears that the two missing NFL players may have died out at sea...

has there ever been another tragedy like this one? of course, the Marshall crash, but that was college... Clemente, Munson, but those were individuals...