If you’ve never encountered wind shear on landing or take off, I can assure you it is a white knuckle experience.
Forty years ago, Pan Am Flight 759 crashed after take-off from New Orleans International Airport (now named Louis Armstrong International Airport) during heavy thunderstorms.
The cause: a microburst (“a dangerous vortex of winds similar to a tornado“) and wind shear, a “rapid change in wind velocity or direction.” The date: 09 July 1982.
All 145 passengers and crew members died in the crash; the impact also killed eight people on the ground in a New Orleans suburb, Kenner. At that time, it was the second deadliest crash in US aviation history.
In 1981, almost 13,000 air-traffic controllers had gone on strike “after negotiations with the federal government to raise their pay and shorten their workweek proved fruitless.”
The job was inherently stressful – workers regularly developed ulcers and high blood pressure … Bob Poli, the [Professional Air Traffic Controllers Organization (PATCO)] president in 1981, stated that nearly 90 percent of the workforce didn’t stay in their jobs long enough to retire due to the job’s brutal stresses.
President Ronald Reagan fired more than 11,000 air traffic controllers in August 1981.
Only “two days after the strike began, the air traffic controllers were gone.” Ironically, PATCO was one of the few unions that had endorsed Reagan in his 1980 campaign for president.
Reagan also declared that no air traffic controller who failed to return to work could be rehired. It took “years to reach pre–August 1981 staffing levels.”
Less than a year after Reagan fired most air traffic controllers, the Pan Am flight crashed after it was cleared for takeoff despite heavy, late afternoon thunderstorms.
Aviation and wind shear
The crash was similar to that of Eastern Air Lines Flight 66, which had crashed due to wind shear on approach at New York’s John F. Kennedy Airpot in June 1975. Of the 124 people on board, 113 died in that crash.
In 1977, two University of Chicago scientists “[hypothesized] the existence of a heretofore unknown form of wind shear (rapid changes in wind speed and direction) they named a ‘downburst’.” Their hypothesis was controversial. Planes continued to crash.
On August 2, 1985, Delta Flight 191 crashed on approach to Dallas Ft. Worth International Airport. The three pilots had “discussed the lightning ‘right ahead of us’” as they attempted to land. The plane entered the thunderstorm, was “violently tossed by the wind” and then crashed into an airport water tank. Killed: 137 people. Injured: 28.
Between 1964 and 1985, “wind shear directly caused or contributed to 26 major civil transport aircraft accidents in the U.S.” Those crashes reportedly killed 620 people and injured 200.
In 1986, NASA and the FAA signed a memorandum of agreement to formally begin the Airborne Wind-Shear Detection and Avoidance Program. It took seven years to “build a foundation” for wind-shear radar systems.
In September 1988, the FAA ordered all commercial aircraft to have forward-looking airborne wind-shear detection and alert systems by 1993. Three airlines—American, Northwest, and Continental— received exemptions until the end of 1995. However, solving the problem was far more complex than originally estimated, and nearly another decade passed before commercial aircraft began to adopt the technology in earnest.
In 1990, the FAA installed “first of a nationwide system of wind shear-detecting radar, called Terminal Doppler Weather Radar,” at Stapleton Airport in Denver.
When a jetliner flies into a microburst on takeoff or landing, the plane faces a sudden headwind, then a tailwind, causing it to lose airspeed and possibly fall to earth.
[…]
The first 47 Terminal Doppler Weather Radars will be installed between 1992 and 1995 in the eastern two-thirds of the country — the area roughly east of Salt Lake City and Phoenix — at airports where thunderstorms are common. An additional 55 radars will be deployed in other locations including the West Coast.
In 1993, President Bill Clinton rescinded Reagan’s ban on striking air traffic controllers. However, “fewer than 10 percent were ever rehired by the Federal Aviation Administration.”
Deadliest crashes
- 25 May 1979. American Airlines Flight 191, Chicago. On takeoff. Killed: 273.
- 11 November 2001. American Airlines Flight 587, New York. On takeoff. Killed: 265.
- 17 July 1996. TWA Flight 800, New York. On takeoff. Killed: 230.
- 16 August 1987. Northwest Airlines 255, Detroit. On takeoff. Killed: 156.
- 09 July 1982. Pan Am Flight 759, New Orleans. On takeoff. Killed: 153.
#scitech, #science (170/365)
📷 World Meteorological Association
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