February 1, 2011

Ice, Sleet and Snow...oh my!

Sitting in line for takeoff in Atlanta this morning
I started a three day trip yesterday with a five leg day passing through Dallas, Ft. Worth, Memphis and Austin before finishing the day in Atlanta where we spent the night. All five leg days are long, but this one went quite smoothly, which was a good thing since we were all expecting significant weather related challenges on day two of our trip. I’ll get to the weather in a minute.

We landed in Atlanta last night after dark with ceilings reported at 200 feet and visibility expressed in feet, not miles. The approach to Atlanta was an interesting one, the ILS/PRM (Simultaneous Close Parallel) approach to runway 10. The procedure is a standard ILS approach with localizer and glideslope indications except that it is too close to a parallel runway (9R in this case) to be flown using normal procedures. The pilot’s must be specially trained to fly such an approach and there is a page long explanation that must be read and reviewed before executing the approach. The procedures call for the pilots to monitor a second tower frequency during the approach to guard against blocked transmissions and the pilots must be alert and ready to immediately follow break out instructions from the tower controller in case another aircraft “blunders” into your airspace. You might find some humor in the word blunder, I know I did, but that is the actual word used in the FAA explanation for this approach. Here’s the actual wording…

“pilots, when directed by ATC to break off an approach, must assume that an aircraft is blundering toward their course and a breakout must be initiated immediately”

I do think it’s important to have a good laugh every now and then and I laughed out loud when I read that line approaching Atlanta last night.

Ice forming on a heated window
As I mentioned before, the weather forecast for DFW predicted a crippling combination of ice, sleet and snow. I woke up early this morning to give myself time to look at the weather and check the status of my flight before heading downstairs to catch the hotel van. Overnight, the DFW area was hit by a thin layer of clear ice, followed by something less than an inch of sleet and ice pellets followed by a shallow layer of snow. Those of you in colder climates may feel free to poke fun at southern US residents and their inability to drive in snow, but I think you would agree that the combination of ice, sleet and snow can be a deadly combination. When I first checked the DFW weather, the wind was blowing from 320 degrees at 29 gusting to 44 knots (KDFW 32029G44KT 2SM TSSNPL BR BKN009 OVC013CB M03/M06) and all the runways were closed. The airport authority at DFW had planned to treat the runways overnight in preparation for today’s weather event, but due to heavy rain, the runways went untreated. As a result the ice, sleet and snow stuck to the runways and it took hours to get even one runway in a condition safe enough for use.

By 9am, DFW had one of it’s seven runways open and that runway was only being used for arrivals. It was another two hours before a second runway was open for use by departing aircraft. The airlines, which had preemptively cancelled hundreds of flights continued to cancel even more as the day went on. In contrast, Dallas Love Field, just miles away was unable to open all day forcing Southwest, Delta and Continental Airlines to cancel every flight out of the airport all day.

Back at the gate in Atlanta and ready to depart, our flight was held on the ground while we waited for word on the condition of the runway. At the time the gate agent finished boarding, the runways at DFW were still closed, but were expected to be open by the time we landed. An hour after our scheduled departure time, we elected to takeoff in hopes that the runways would in fact be open when we arrived. Of course, we had an alternate airport planned in case the runways were still closed when we arrived, but we certainly hoped we wouldn’t need it.

We departed Atlanta where the visibility was still hovering around CATII minimums and headed toward DFW. Just as we leveled off at FL340, we received word that one runway was open at DFW and we would be able to land. The runway was covered in ice and snow, but a short time later we were informed that several company jets had landed and reported braking action good.

Our flight plans have a column indicating forecast ride conditions. The ride forecast comes from a combination of actual reports from other aircraft and the professional opinion of a meteorologist. The forecast is expressed as a number between 0 and 5...0 being a perfectly smooth ride and 5 being something like the inside of an F5 tornado. Our ride prediction for today’s flight was a 3...not good. The ride in was terrible with moderate chop and turbulence for most of the flight. We tried various altitudes, high and low, to find a smooth ride, but it just didn’t happen. The flight attendants stayed in their seats and I kept the cabin as cool as possible without freezing people out in an effort to prevent a chain reaction of air sickness.

The landing at DFW was actually a little anti-climactic. By the time we arrived, the precipitation had ended and the airport had successfully opened two runways. We landed on runway 31R while 31L was being utilized for takeoff operations only. The runway was completely covered in ice and snow, but the braking action reports were all good and although the wind, still peaking at 40+ knots was strong, it also meant that when we touched down, we were just that much closer to taxi speed which of course just shortens our landing distance.

The biggest problem I had was getting home. My car was literally frozen to the pavement in the employee lot and the drive home that usually takes 20 minutes on a good day and 25 minutes in the heat of rush hour traffic took an hour and a half. The rest of my trip was canceled and scheduling put me on reserve beginning at 3am in the morning. I really hope they don’t call…not sure if I could get to the airport anyway. We’ll see.

12 comments:

  1. We now know they called.. ;-)

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  2. I don't get what cold temperatures make to air sickness:"I kept the cabin as cool as possible without freezing people out in an effort to prevent a chain reaction of air sickness."can you explain it to me
    Ignacio

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  3. Glad you were able to make it back home. I had to head to DEN for New Hire Orientation with Frontier. I wasn't planning on staying the night in DEN, so I didn't have any clean clothes or other supplies, but thankfully the Frontier crew was able to get us into OKC safely a little after midnight, and right before the airport was closed.

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  4. Ignacio, Any flight attendant will tell you that a warm cabin and turbulence is a bad combination that usually results in the use of air sick bags. Keeping the cabin cool seems to prevent at least some people from becoming ill. I always cool the cabin down a few degrees during a rough flight.

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  5. the ice picture: was it taken enroute? if so, how do you react to that? I don't mean how do you remove the ice, but did that concern you? If I were in 14a looking out the window and saw ice I wouldn't be too calm. And good call on the cool cabin...I got air sick once and I would imagine that a warm cabin would have just made it that much more worse.

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  6. This is kind of an unrelated question to your post although it has to do with approaches. Some of my pilot friends and I were wondering what were the GPS/RNAV approach capabilities of the MD-80. I am currently flying the mighty C172 with GPS and WAAS which enables me to use GPS generated glide paths to get down to just above CATI ILS mins. Now I am fairly sure you are not WAAS equipped but I believe that you have a LNAV/VNAV system. Although I am not sure whether you are certified for that or even LNAV approaches. Thanks, keep the posts coming there great.

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  7. Joanna, The ice is not a serious concern while flying. On the ground, the ice and snow falls onto areas that are not protected by anti-ice and de-ice equipment and must be removed before flight. The ice that forms in flight is always on areas that are heated (at least on a passenger jet). The ice on my window that day was not unusual and was removed by window heat. You would never see ice on your window at 14a;)

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  8. Erich, Currently, our MD80s are qualified to fly RNAV approaches to LNAV mins. Our GPS displays glide slope information when flying RNAV, VOR and NDB overlay approaches and we are trained to fly a GPS generated glideslope all the way to minimums. There is no VNAV button on our MD80s, so we must manually control our vertical speed to stay on glide path. Most guys do this with the AP on to simplify the approach. Problem is that LNAV mins don't get you very low, so we usually fly ILS approaches...available just about everywhere we fly.

    BTW, there is an email button on the right side of the blog if you ever want to email me directly. Thanks for the question.

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  9. thanks for the clarification. See, now I will be more calm about icy conditiions. I just know that planes have crashed due to ice on wings, so when I hear ice I hear crash.

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  10. I've been using the cold air method to prevent motion sickness on myself and my kids for years. When driving the hilly up and down canyon passages in California, my kids tend to get a little car sick, but to prevent that I kick on a/c just enough to keep cool air flowing rather rapidly. For whatever reason, people are less likely to throw up when cool air is blowing in their face; it really works!

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  11. I really like this blog because i love ice.

    Education

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  12. thanks for share..

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