Air Caribbean Flight 309 was a domestic, non-scheduled airline flight by Puerto Rican airline Air Caribbean, which on September 26, 1978, crashed as it was preparing to land at Luis Muñoz Marín International Airport (then known, unofficially, as Isla Verde International Airport) in San Juan, after a flight from Ramey Air Force Base (what is now known as Rafael Hernandez Airport) in Aguadilla, killing all six occupants of the aircraft and injuring several customers of a Barrio Obrero bar over which the airplane fell.

The flight that day was being carried on a Beechcraft D18S which was owned by Puerto Rican businessman and pilot Francisco Cruz, who sometimes leased this airplane, registered as N-500L, to Air Caribbean.

The airplanes were so close, however, that an Eastern pilot who was riding jump-seat on the L-1011 later testified he could see the Beech's passengers' silhouettes from his vantage point.

[3] The Eastern Air Lines airplane landed safely at the airport, with no injuries reported among the crew and passengers on that aircraft.

Family members of those killed in the crash and some of the injured at the bar filed a class-action lawsuit against Air Caribbean, Eastern Airlines, the Federal Aviation Administration, Francisco Cruz and Cornhill Insurance (which represented the Lloyd's of London firm in this case).