February 20, 1981: Boeing 707 Nearly Hits Television Mast atop World Trade Center

A Boeing 707 belonging to an Argentine airline comes close to hitting the television mast atop the World Trade Center’s North Tower. The plane is flying in clouds at 1,500 feet, instead of at its assigned altitude of 3,000 feet, and descending toward Kennedy Airport. About four miles, or less than 90 seconds, from the WTC, the Terminal Radar Approach Control (TRACON) in Hempstead, Long Island, becomes aware of the situation thanks to a new automated alarm system and is able to radio the pilot with the order to climb. The alarm system that sounds, called Minimum Safe Altitude Warning, has been in operation for about a year. When radar shows a plane at an altitude within 500 feet of the highest obstruction in a particular area and 30 seconds away, a buzzer sounds repeatedly at the TRACON. At the same time, the letters LA (for low altitude) flash on the radar scope next to the plane’s blip. [New York Times, 2/26/1981]