FAA’s ‘Operation Bongo Mark 2’ Proved Supersonic Flights Over Land Weren’t Feasible

Convair B-58A Hustler in flight (S/N 59-2442). Photo taken on June 29, 1967. (U.S. Air Force photo)

Sonic booms caused too much damage to be allowed over land in the continental United States.

On February 3, 1964, The Federal Aviation Administration launched Operation Bongo Mark 2 to investigate the effects of supersonic transport (SST) flights on cities. The experiment was managed by the FAA, NASA, and the USAF. Public opinion, crucial to the experiment, was captured by the University of Chicago’s National Opinion Research Center.

Bongo Mark 2 was not the first series of tests undertaken to measure the effects. In 1958 and 1960, tests were conducted at Wallops Island, VA. In 1960 and 1961 tests took place at Nellis Air Force Base outside Las Vegas, NV. St. Louis MO was a test site in 1961 and 1962.

The difference between these previous tests and the Oklahoma City tests was that the sonic boom’s effects on buildings and structures, as well as on the general public and their opinions about living with sonic booms as a more or less regular occurrence were not the primary premise for the previous tests. Operation Bongo Mark 2 would be the largest and most comprehensive test of its kind.

Beginning on February 3, 1964, Convair B-58 Hustler supersonic bombers along with Lockheed F-104 Starfighter, Convair F-106 Delta Dart, and McDonnell F-101 Voodoo supersonic interceptors, flew through the sound barrier at low altitude over Oklahoma City an average of 8 times per day. The effects of the sonic booms behind the aircraft were roughly 16 miles wide.

The flights were scheduled so that the sonic booms would be timed somewhat consistently, usually beginning at 0700 local time each day and ending in the afternoon. The residents of the city actually timed some of their activities by the sonic booms. It was said that some downtown construction workers began to take their lunch breaks based on the noontime boom.

When the testing concluded on July 29, 1964, a total of 1,253 sonic booms were created by the supersonic flights over the city. 147 windows were broken in two of the city’s tallest buildings over the first 14 weeks of the experiment. Even though there were nearly 10,000 complaints of damage to buildings (mostly cracked plaster and glass breakage), the public opinion about living with daily sonic booms indicated that 73% of the subjects said they live with the booms. 25% of the subjects believed they could not live with the booms. About 3% of the Oklahoma City residents (at that time roughly 15,000 people) were upset enough to write, phone, sue, or otherwise take action to protest the experiment.

The lasting effects of Operation Bongo Mark 2 were the cancellation of Boeing’s 2707 supersonic transport design. Eventually the United States withdrew from SST design altogether, leaving Aerospatiale/BAC (Concorde) and Tupelov (TU-144) as the only builders of SSTs. Beginning in 1973, supersonic flight over the United States and its territorial waters was banned. The Concorde SST, eventually operated by several airlines and used in regularly scheduled service to and from the United States, was forced to decelerate to subsonic speeds offshore.