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Tag: turbulence

The line was moving

Part three of a three-part series. Read parts one and two here.

 

Finally, departures opened up, and we got our final, this-is-for-real route. Tower was now advertising a runway we could all use, but the line was a long one: When we pushed back, we were number thirty-plus for takeoff. But the line was moving, and in our case, it was moving faster than the clock, so we’d get out before we timed out and couldn’t legally fly. Neither of us relished the possibility of having to go back to the gate and explain to the passengers that we couldn’t legally fly.

The only route out of Denver was still a west one, and we flew most of the way to the western border of Colorado before turning north, and eventually east. On the radio, we heard an awful lot of airplanes getting holding patterns for Denver—and now crews weren’t just talking about diverting, they were diverting, and some weren’t even waiting.

As we flew east, the ride deteriorated to “moderate-plus” chop. It was awful, even after slowing down. We had to head southeast to avoid both traffic and weather. On the radar, we saw a couple of holes beyond what we could see out the window. I sent a message to our dispatcher asking about a possible new route that was south of what we were filed for. We didn’t have much time, however, because we were headed right to the worst of the line of east-west storms.

Dispatch liked what we suggested and sent us a specific route to request, which I passed on to Center. It took longer to get it back than I anticipated, but we got approved for a route that would ultimately save us nearly 20 minutes. The ride didn’t improve for nearly 90 minutes, but it finally smoothed out enough to let the passengers get up, which allowed us to get our dinner. The weather in Newark was clear and breezy. Thank goodness for small favors.

We landed nearly three and one-half hours behind schedule, exhausted and relieved to be on the ground. I had not had a day like that in a long time, and I was overdue for one. My flight home, it turns out, had cancelled, which was actually a relief—I’d hate to think that I had just missed it. I headed off to my crash pad to get some sleep. The mid-morning flight was wide open, probably because of other missed connections from the night before. But I didn’t care. I was going home.—Chip Wright

National Wind Turbine Map: A new Pilot Resource

As one of the fastest growing forms of renewable energy, wind turbines are sprouting up all over the country.  On a recent airline flight across the country, I was blown away to see areas in northern Texas with rows of wind-turbines that went on for miles—some of which included well over of a hundred turbines. Now I know why they call them wind farms!  This technology is increasingly popular in rural Alaska, where the cost of fuel to generate electricity is through the roof expensive.  As with all good things, they come with potential impacts.  As pilots, wind turbines provide several challenges: initially as obstructions we have to avoid during flight.  If located too close to airports, they interfere with instrument approaches resulting in higher minimums and reduced access.  Finally, when the wind  blows they represent a source of turbulence, which we still have much to learn about (more on that later).

Interface to the Interactive Wind Farm Map, starts with an overview of where towers are found around the country.

Interface to the Interactive Wind Farm Map, starts with an overview of where towers are found around the country.

Locating individual wind turbines
Recently the US Geological Survey has given us a new tool to locate wind turbines, on a nation-wide basis.  A new interactive mapping application, provides access to a database that not only shows us where wind turbines are found, but records their height, blade length, and other information on a tower-by-tower basis. Prior to this, while some states captured the locations of individual wind turbines, there was no uniform database that provided this information across the country.  Starting with the FAA’s Digital Obstruction File (through July 22, 2013), a USGS team led by Dr. Jay Diffendorfer located over 47,000 turbine sites, verifying individual tower locations with high-resolution satellite imagery. This data base gives us a much better way to find individual tower locations, with a location accuracy estimated to be within 10 meters.

While fewer in number, wind turbines are sprouting up across Alaska.

While still few in number, wind turbines are sprouting up across Alaska.

A row of wind turbines just outside Unalalkeet, on the west coast of Alaska. According to the USGS interactive map, they have a total height of 156 ft. tall

A row of wind turbines just outside Unalalkeet, on the west coast of Alaska. According to the USGS interactive map, they have a total height of 156 ft. tall

Understanding impacts
This database is designed to support research into environmental effects on both critters that fly, and wildlife habitat.  But these data may also be useful in the future to project the impact of down-wind effects on general aviation airports, which is still an evolving research topic.  A recent study at the University of Kansas has shown that the turbulence from a wind turbine extends further as wind speed increases, up to 3 miles in some cases.  This and the potential increase in cross winds could be a significant impact for small aircraft at GA airports.  Hopefully, more work will be done to quantify these conditions, leading to improvements in the FAA’s obstruction review process, which today only takes into account the height of an obstruction above ground when air space reviews are conducted.

Provide feedback
All maps are only as current as the date used to make them.  This data set incorporated information from FAA’s obstruction file as of last July.  And if you come across wind turbines that aren’t in the database, please capture what information you can and send an email with the location to [email protected].

Thanks to this effort, we have a better way to learn where wind turbines are located in the areas where we fly!

Alaska Aviation Weather Forecast Changes and Enhancements

Update:  Due to the government shutdown, the changes described below have been delayed, and are planned to go into effect on November 12.

The weather is still one of the most important factors we need to evaluate before each flight.  Whether you fly VFR or IFR, knowing the current conditions and how they are expected to change is critical to that all important GO/NO GO decision,  figuring out which route to take, and what to watch for inflight.  On October 15th, the Alaska Aviation Weather Unit (AAWU) will make changes that should help you make those decisions, as you plan to fly.  Here are some of the changes.

Area Forecast/Airmets
Starting in mid-October, new Area Forecasts (FA’s) will be issued three times a day—at 4:15 a.m., 12:15 p.m. and 8:15 p.m., local Alaska time.  Updates will come out at 12:15 a.m., 6:15 a.m. and 6:15 p.m.—or as needed if things are changing faster than anticipated.  AIRMETs will be either issued or updated using a similar schedule, the details of which may be found on the AAWU website at: aawu.arh.noaa.gov/changes/

Icing and Turbulence Graphics
In a trend which I find helpful, more information is being presented in graphic form.  Starting on Oct 15, the AAWU will issue new icing and turbulence graphics, showing the forecast in three-hour time slices, as opposed to the 6 hour charts we have been using.  Found under the Graphical Forecast tab on their home page, in the sample Icing Forecast product below, the user has a choice of viewing a single 12 hour summary, or on the bar immediately above the product, selecting one of the three-hour charts to see how the forecasters expect conditions to develop during the day.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Individual charts showing 3 hour intervals show how conditions are expected to develop.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Users can select individual charts showing 3 hour intervals to see how conditions are expected to develop.

Another change is that the Turbulence Forecast will be split into separate low and high altitude products.  Along the top, in the sample image below, the user again has the option to look at the 12 hour summary— showing the entire forecast period—or can mouse-over a progression of graphics to see how the turbulence is expected to develop during the forecast period.  Note that while the products are split at Flight Level 180, if conditions span that flight level, they will be depicted on both sets of products.  A little time spent examining the legend to become familiar with the new conventions will help become accustomed to these products.

sample turbulence lo level

Sample low altitude turbulence product, covering a 3 hour period. Users may also select the 12 hour summary chart to get the “big picture.”

A more subtle difference in the product to note:  An additional turbulence category, “Isolated Moderate” is being added. Previously the products only depicted “Occasional Moderate” and “Isolated Moderate to Severe” conditions.

table 2 issuance times

Table showing when both graphic and text products will be updated. Helpful if the weather is bad and you are waiting for the next forecast!

Other graphic products, such as the Surface Map and IFR/MVFR Chart won’t change, however the issuance and update times will.  The AAWU has provided a table (above) summarizing the timing of both text and graphic product which provide a roadmap to the new scheme.

These are significant enhancements to the products available to Alaskan pilots, and a downloadable document summarizing them is available online that contains examples and a more complete description of the schedules and changes.  If you have feedback on products, the National Weather Service would like to hear it. An easy way to reach them is to shoot an email to mailto:[email protected].

As pilots we need to remember that the accuracy of these products is influenced by the PIREPs we file, either confirming forecast conditions, or alerting forecasters when conditions are changing faster than expected. Please take time to file an extra PIREP or two as you fly.

So a modification to an old adage might be… “If you don’t like the weather you see at the moment, just wait for the new forecast.”  Thanks to these changes, the new forecasts will be showing up more graphically and more frequently than before.

The only thing faster than the airplane is information

It is amazing the contrasts in government efficiency–or the lack thereof–that exist every day. For instance, the FAA has spent billions to get the NextGen ATC system off the ground, and for all of that, we still have NowGen and YesterGen. Likewise, as my AME likes to say, the pilots are flying in 2012, but the FAA is practicing medicine in 1960-something. On the other end of the spectrum is the IRS. Get their attention, and you will be hearing about it immediately. They don’t mess around.

But, for all of the bad FAA jokes (my favorite: I’m from the FAA and I’m not happy until you’re not happy), the feds are by and large good people who do the best they can with the tools they have been given, which means they aren’t any different than you and me. I recently got a reminder that when they need to do something fast, they can.

I recently had an encounter with severe turbulence while climbing out of Baltimore. It was a short encounter, and not all that unexpected because of the weather. But, as with any encounter so severe, it got my intention. So, being the dutiful air-person and practitioner of air-person-ship that I am, I reported it to ATC.

The Washington Center controller asked a flurry of questions, and I responded with a flurry of information: altitude, exact location, a description of what happened. Every other airplane on the frequency immediately wanted to know where it was, and they requested deviations away from my little find.

The controller began by asking all flights climbing and descending in our area for ride reports. All the flights were in 737s or bigger, and they all reported “moderate” or “heavy moderate,” and you could hear the bounces in their voices. This made sense, because the CRJ that I fly has short, skinny wings, and it does not absorb turbulence very well at all. What would be severe to us might very well not be to something bigger; of course, the reverse applies as well.

What was so impressive was how quickly the word got out. On every frequency that I used for the balance of our flight to Cincinnati, the controller was issuing the pilot report about our encounter. On the first frequency change, as we were checking in, he was reading the news to everyone in his sector. I told him that we were the reporting aircraft, and he had a couple of follow-up questions, mostly pertaining to the accuracy of his information. It was spot on. It was quick, accurate, and given the proper sense of urgency.

When we landed, I called a friend of mine used to fly for us. He now flies for Southwest and was getting ready to commute to work from Providence, R.I. I told him to be ready for a bumpy ride, and relayed our experience. When he arrived in Baltimore, he called me back and said that the ride into BWI on the 737 flight he took was “737 moderate, and borderline RJ severe. That was a good call, and I’m glad I wasn’t there.”

I wish I hadn’t been either, but I’m glad that the FAA has the means to disseminate that kind of critical information as quickly as it did. Of course, these are the folks who got thousands of airplanes on the ground on September 11, 2001, in record time, so they deserve credit where credit is due.—By Chip Wright