Saturday, July 2, 1994, was hot and humid when USAir Flight 1016 took off from Columbia, SC to Charlotte, NC. The plane carried the usual mix of passengers, including a couple embarking on their honeymoon and an entire family that had never before flown.
As the aircraft approached the north end of the runway at Charlotte-Douglas International Airport, an intense thunderstorm was in progress. While the captain and first officer discussed the storm as they flew the final approach, evasive action was not taken until they encountered intense wind shear inside a wall of heavy rain. By then, it was too late. The DC-9 cut a grotesque path through a thick stand of trees to the right of the runway, then crashed on the west side of the airport. Thirty-seven perished.
Sunday papers across the United States featured depressingly familiar headlines about a wind shear claiming yet another airliner.
Today, twenty years later, we remember the Charlotte tragedy and celebrate a major scientific achievement: The defeat of the downburst – sometimes also referred to as a microburst.
An anguishing history
July 23, 1973, Ozark Airlines Flight 809 crashed in a thunderstorm on approach to St. Louis’ Lambert International Airport. The National Transportation Safety Board (NTSB) cited confusion about the weather and the thunderstorm’s “downdraft” forcing the aircraft into the ground as the cause. Thirty-eight died.
Less than two years later, Eastern Air Lines Flight 66 crashed at John F. Kennedy Airport in New York, killing 113 at the time, the largest U.S. death toll in the crash of a single airliner. The NTSB blamed “adverse winds” for the crash.
After a meteorological investigation of the crash of Flight 66, the University of Chicago’s Dr. Ted Fujita and Dr. Horace Byers published a paper in early 1977 hypothesizing the existence of a heretofore unknown form of wind shear (rapid changes in wind speed and direction) they named a “downburst.”
Their paper produced the fiercest controversy in the history of the application of weather science. Numerous meteorologists and aviation experts did not agree with Fujita’s hypothesis and believed he had misinterpreted the evidence. Their minds were not changed even as a mind-boggling (by today’s standards) number of aircraft accidents and incidents continued to occur:
- Continental Airlines Flight 426, Denver, 1975
- Allegheny Airlines Flight 121, Philadelphia, 1976
- Continental Airlines Flight 63, Tucson, 1977
- USAir Flight 179, Dayton, 1982
- Pan American Flight 759, New Orleans, 1982
- USAir Flight 183, Detroit, 1984
- United Airlines Flight 663, Denver, 1984
Downburst-driven wind shear, for many years, was the leading cause of airline accidents. Not listed above was a near-miss involving Air Force One carrying President Reagan. A downburst occurred immediately after it landed at Andrews Air Force Base in August, 1983. The airfield anemometer (wind speed instrument) clocked a peak gust of 150 mph. That such a close call involving Air Force One could occur was evidence of the deep skepticism involving Dr. Fujita’s hypothesis.
On August 2, 1985, a Delta Airlines jumbo jet was on approach to Dallas Ft. Worth International Airport while the three pilots in the cockpit discussed the lightning “right ahead of us.” The Lockheed L-1011 aircraft penetrated the thunderstorm and was violently tossed by the wind. The plane slammed into a water tank at the airport. The crash of Delta Flight 191 caused the deaths of 137 people and injuries to 28.
The modern L-1011 was equipped with a digital flight data recorder (also known as a “black box”) that recorded many more aspects of the flight’s final minutes than analog flight recorders on the jets involved in the earlier crashes. Dr. Fujita was able to use this data, plus the instruments at the airport, to conclusively prove that a downburst had caused the crash.
Science to the rescue
Almost overnight, the political and scientific winds shifted.
The Federal Aviation Administration rushed a wind shear avoidance and escape training course into production. Wind shear detection systems were installed and 44 airports received Terminal Doppler Weather Radars (four of which are in the Washington-Baltimore area, the most of any metropolitan area in the U.S.).
It still took time for flight instructors and crews to fully understand the magnitude of the threat, thus the crash in Charlotte. Since that time, flight simulators and classroom training teaches pilots to avoid wind shear. If they inadvertently enter it, they are taught the optimal ways to escape.
Downbursts still affect airports. In May, 2009, the downburst that caused the collapse of the Dallas Cowboys’ practice facility moved across DFW International about ten minutes earlier. The wind shear alarms went off and, unlike in 1985, there was no accident or incident.
While the possibility of a future accident cannot be completely ruled out, the fact is that weather science has made flying much safer than just two decades ago. But, there is still work to be done. As recently as June 7, a Boeing 737 on approach to St. Louis’ Lambert International Airport flew dangerously close to a tornado causing damage just west of the airport. This is one of several tornado-related aviation incidents in recent years.
Still, the work of Dr. Fujita represents science at its best and, given the growth of aviation, has saved hundreds, if not more than a thousand, lives.
Mike Smith is Sr. Vice President of AccuWeather Enterprise Solutions, a certified consulting meteorologist and a Fellow of the American Meteorological Society.
The full story of how weather science saves lives in tornadoes, hurricanes, and downbursts is told in his book, Warnings: The True Story of How Science Tamed the Weather (Greenleaf Book Group)