Thursday, July 11, 2013

"What Are You, Some Kind of Expert?"

Today, conditions were perfect for microbursts around Dallas-Ft. Worth International Airport. When I went to the F.A.A.'s web site, I was surprised there were no adjustments being made in air traffic for the threat. So, since I was a passenger on a flight that was going to depart in a few minutes, I walked up to the flight crew and introduced myself.

While very polite, I was surprised by their lack of situational awareness. The temperature at the airport was 98°. I asked about the dew point. They didn't know and told me they did not have access to that information unless they requested it in the cockpit. I looked it up: 63°. Those are perfect values of temperature and dew point to get microbursts.

I showed the pilots the radar below. There were two "outflow boundaries" (purple and yellow dashed lines) the intersected over the west side of the airport. I said that I expected the developing cell on the west side of the airport (blue symbol is our location) to intensify and drift south.

The pilots looked at each other then looked at me: "Are you some kind of expert?"
Me: Yes.
Captain: Where do you work? Do you get paid to do this type of work?
Me: Yes, I do. I work at AccuWeather.

That seemed to get their attention. They spent a little more time looking at the weather on their terminal.

Minutes later, two microbursts. The one near Grapevine was affecting the northwest edge of the airport.

Six minutes later the Grapevine microburst was maturing while the Cockrell Hill microburst played out.

About this time, the FAA shut down take offs and landing because of the hazard at both Dallas airports.

And, here is the visual of the downburst-rain shaft south of the west runway complex at DFW. I took this seconds before a cloud-to-ground lightning (CG) bolt occurred. Microbursts often produce CG's.

The NOAA GOES satellite WINDEX showed those thunderstorms had the potential to produce gusts to 64 knots (74 mph) which, under the right conditions, could down an aircraft. The arrow points to the thunderhead south of the airport which produced the rain shaft above.

On August 2, 1985, a jumbo jet crashed in a microburst at this same airport killing 137. Today, other than some flight delays, nothing happened. What used to be the #1 cause of airline accidents has been "tamed" by weather science. Those pilots undoubtedly have flown the 1985 microburst in a simulator (so they could escape if they accidentally get into a microburst). The Terminal Doppler Weather Radar and Low Level Wind Shear detection system worked today and kept everyone safe -- as well as preventing the loss of an aircraft worth tens of millions of dollars. Warnings: The True Story of Science Tamed the Weather tells the story of Dr. Ted Fujita and the other scientists that bravely bucked the consensus in aviation and meteorology to put an end to these crashes. The last wind shear crash occurred 19 years ago.


  1. Mike, thanks for that great discussion and your commitment to public safety! While you were displeased with the pilot's lack of situational awareness, what is your level of confidence that the TDAL terminal doppler radar would have detected these microbursts and sounded the alarms with appropriate lead-time for pilots?

    I'm not excusing them, but the pilot's lack of awareness tells me they're probably depending on that technology.

  2. This account appears to me to demonstrate that the sophisticated systems developed since the 1985 Delta crash at DFW work as they should. One (at least I) would hardly expect air crews to be expert meteorologists. That's what specialization and 'division of labor" are all about.

    My expectation of pilot "situational awareness" at DFW in 2013 would be that if the sophisticated systems were "down" and the pilot saw a weather cell in the vicinity, he would decline to land or take off until the visible threat ended.

  3. @Dryslot. The illustrations are of the Terminal Doppler Weather Radar. I suspect the control tower alarm went off when it detected the Grapevine microburst. It is also possible the northwesternmost LLWAS (Low Level Wind Shear Alert System) at DFW alarmed.

    Since writing the above a delayed report came in of trees snapped in Ft. Worth about 30 minutes after the photo of the microburst. I strongly suspect a microburst took out the trees in Trinity Park.

  4. Great post Mike!

    I have a friend that worked at on the Terminal Doppler Radars for Lincoln Labs back in the 90s. He will love your story

    Scott Sabol


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