Clemente spent much of his time during the off-season involved in charity work. When Managua, the capital city of Nicaragua, was affected by a massive earthquake on December 23, 1972, Clemente (who visited Managua three weeks before the quake) immediately set to work arranging emergency relief flights. He soon learned, however, that the aid packages on the first three flights had been diverted by corrupt officials of the Somoza government, never reaching victims of the quake. He decided to accompany the fourth relief flight, hoping that his presence would ensure that the aid would be delivered to the survivors. The airplane he chartered for a New Year's Eve flight, a Douglas DC-7 cargo plane, had a history of mechanical problems and an insufficient number of flight personnel (missing both a flight engineer and copilot), and was overloaded by . It crashed into the Atlantic Ocean off the coast of Isla Verde, Puerto Rico immediately after takeoff on December 31, 1972, due to engine failure.