American Airlines Flight 320

American Airlines Flight 320 was a scheduled flight between Chicago Midway Airport and New York City's LaGuardia Airport. On February 3, 1959, the Lockheed L-188 Electra performing the flight crashed into the East River during its approach to LaGuardia Airport, killing 65 of the 73 people on board. Weather conditions in the area were poor, and the aircraft descended through dense clouds and fog. As it approached the runway, it flew lower than the intended path and crashed into the icy river 4,900 feet (1,500 m) short of the runway. At the time of the crash, American Airlines had been flying the newly-developed Lockheed Electra in commercial service for only about two weeks, and the accident was the first involving the aircraft type.

After the crash, surviving flight crew members said that they had been monitoring the aircraft's instruments, and right up to the moment of impact, the altimeter had been showing that they were flying a safe distance above the water. However, eyewitnesses who saw the aircraft from the ground said that it seemed to be flying much lower than other planes normally flew as they approached the airport. An investigation by the Civil Aeronautics Board concluded that the crew made several mistakes that caused the crash; the crew's inexperience flying the Lockheed Electra and the poor weather conditions were contributing factors. The Air Line Pilots Association disputed that finding, and said the accident was caused by faulty instruments in the aircraft and by poor weather conditions, not by any mistakes made by the highly experienced flight crew. The accident led to proposals for new regulations requiring flight recorders in large passenger aircraft, and to new construction at LaGuardia Airport to extend the runways, improve the approach lighting systems, and add an instrument landing system to the runway that Flight 320 had been approaching.