Wind Shear Tragedy: Delta Flight 191, August 2, 1985

Noctilucent Clouds Dazzle Eyes over Canada
June 22, 2016

Wind Shear Tragedy: Delta Flight 191, August 2, 1985

On August 2, 1985 a tragic air disaster unfolded at the Dallas-Fort Worth International Airport. It would become one of the deadliest weather-related incidents in U.S. aviation history. The seeds for this very tragic day in the Metroplex lay in a hot humid air mass, a weak cold front, poor communication, and poor judgement.

North Texas summers run on the brutal side with 100-degree temperatures and Heat Indexes to 105 common. August 2, 1985 was no exception; by late afternoon the DFW International Airport reported a temperature of 101 degrees with a dew-point of 67 – making for a super-uncomfortable Heat Index of 107 degrees. Such conditions also create a very unstable environment weather-wise…the slightest bit of “help” from a front, trough or what have you can lead to violent thunderstorms. Such a front was draped across north Texas on that day as shown here:

Surface map from 7 a.m. August 2, 1985.

Surface map from 7 a.m. August 2, 1985.

Between five and six p.m. scattered, relatively moderate thunderstorms began forming over north Texas, a few of them just north of the DFW airport.

Enter Delta Flight 191, winging its way west from Fort Lauderdale. Shortly after 5 p.m. controllers steered the incoming flight around a cluster of these storms, onto a safer route approaching from the north.  However, more storms began firing along the flight path. Controllers didn’t seem especially concerned, calling these new developments “small showers”- apparently neither was the flight crew.

By 6 p.m., the airliner was heading into its final approach, about five miles out and at around 2,500 feet. As Flight 191 made the move to begin landing flight crew members, including the captain, noted that lightning was coming from the storm, as recorded on the Cockpit Voice Recorder (CVR). They had time to change course, i.e. “go around” and attempt the landing again, but did not.

As Delta 191 continued its descent for landing it encountered strong headwinds from the storm. The crew reacted by increasing power. Moving at about 180 mph (three miles per minute), the jet was on the opposite side of the small but very intense storm core less than 30 seconds later, and began encountering a stiff tail wind. This reduced the available air flow and lift under the wings.  The downward gush (microburst) of air coming out of the storm also caused the altitude to decrease much faster than planned, essentially pushing the plane toward the ground at 50 feet per second. According to the Flight Data Recorder, the crew fought frantically to slow the descent, and was able to reduce it to about 10 feet per second before it contacted the ground. The aircraft had encountered severe wind shear: a sudden change of wind direction, speed, or both over a short distance.

The plane first touched down in a field a little over a mile short of the runway; for a few seconds it bounced along the ground intact before it crossed Texas Highway 114, killing a motorist when its left engine crushed the vehicle.

flight_191_crashpathFlames began to stream along the wings and fuselage after the plane struck two light-poles near the highway; fire spread from the wing, entered the cabin and moved very rapidly, spurred along by the escaping jet fuel and 150-mph forward speed.  Shortly thereafter the L-1011 crashed into two huge water tanks at the edge of DFW airport where it burst into a ball of fire and broke apart. The tail section became a lifeboat for some passengers; they escaped the bulk of the inferno as the section was blown back away from the rest of the wreckage.

Surviving flight attendant Wendy Robinson Fernsell was seated at the back of the plane near the exit door. She told the Palm Beach Post in 2015, that there was “a fireball coming down the aisle”, but the plane broke apart and torrential rain extinguished the flames just as they were making their way into the rear section. Some survivors suffered extensive burns but about a dozen of them walked away with only minor injuries. No one forward of row 21 survived; most of the survivors were in the smoking section from row 35 and rearward.

According to National Weather Service data, winds reached 80 mph at the airport in the half hour after the crash. This was truly an extreme storm; pilots awaiting takeoff described it as a “wall of water”, some even said they saw a tornado.

The death toll of 137 makes it the worst air disaster in Texas history and one of the worst weather-related airline crashes in U.S. record books.

How could such a horrible storm have gone unnoticed? Well, the information we take for granted now –Doppler-derived wind speeds, for instance – simply did not exist at airports in 1985. Microbursts were also not completely understood or easily forecast.  Furthermore, the air controllers for whatever reason underestimated the severity of the thunderstorm, despite numerous reports from observers on the ground and other pilots.

The tail section, where most of the survivors were seated / Fort Worth Str-Telegram

The tail section, where most of the survivors were seated / Fort Worth Star-Telegram

Nationwide Terminal Doppler radars installed in the years that followed the crash now allow controllers to identify wind shear threats much more accurately. Had this been available in 1985, there’s no doubt the pilot would have been “waved off” before flying into such a vicious storm. The NTSB ruled that pilot error was the chief cause of the crash, that the Captain and cockpit crew should have known given their training and experience that a thunderstorm producing lightning needed to be avoided instead of flying through it. The poor data sharing from controllers was a contributing factor, but less significant than the faulty judgment of the flight crew.

Thanks to the hard work of engineers and scientists, such a crash, while certainly possible, is very unlikely today.


Steve LaNore
Steve LaNore
Steve LaNore is a Certified Broadcast Meteorologist with decades of experience. His books "Twister Tales" and "Weather Wits and Science Snickers" are available on Amazon. He is the winner of the Texas Associated Press Broadcasters (TAPB) "Best Weathercast" in 2014 / Oklahoma Associated Press Broadcasters "Best Weather Coverage" in 2015, Oklahoma Association of Broadcasters (OAB) "Best Weathercast" 2006, 2008, 2009 / Winner of three awards for "Weather Wits and Science Snickers" in 2013 / LaNore has a heart for weather history, debunking weather myths and making science understandable.

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