Cubana de Aviación Flight 493, registration CU-T188, was a Douglas DC-4 en route from Miami, Florida, to Havana, Cuba, on April 25, 1951.

A US Navy Beechcraft SNB-1 Kansan, BuNo 39939, was on an instrument training flight in the vicinity of Naval Air Station Key West, Florida, at the same time.

The four-motored transport, with 34 passengers and five crewmen, power-dived into the ocean a half-mile offshore at a speed estimated by onlookers at 600 miles an hour and sank in water 20 feet deep.

The Navy plane, a twin-engined Beechcraft with a crew of four on a routine instrument-training flight, went to pieces as it fell and crashed two miles west of the transport.

R. S. Quackenbush Jr., commanding officer of the Boca Chica Naval Air Station here, said that in such cases "one of the pilots has clear visual observation at all times."

The fuselage, which rolled up like a ball on impact with the water, will not be raised until morning, but the Navy craft used searchlights to continue the hunt for more bodies through the night.

The probable cause of the accident was given by the CAA as a failure on the parts of both air crews to exercise due vigilance in looking for and avoiding conflicting traffic.