Proficiency: Convective primer

Practical tips for dealing with thunderstorm season

April 1, 2013

thunderstorms

In the airline world there’s a saying: Why look at the weather when we’re going anyway? It’s not really true, by the way. We’re as concerned as any pilot, but we have better tools to work around the problem—mainly the ability to get above most of the weather and a 450-knot true airspeed to make large deviations around it when needed. Even a large jet is no match for Mother Nature’s towering, churning cauldrons of heavy moisture, frequent lightning, and severe turbulence.

I learned to fly in the Northeast and if one doesn’t learn how to deal with the weather there, one wouldn’t get very far from the local airport. When it comes to thunderstorms, I learned that the late morning hours usually bring a lull in storm activity. The morning storms typically have dissipated and the heating of the day has not yet boiled up new ones. So I learned to make many of my summer cross-countries at that time of day. Of course, storms associated with a front can come at any time of day, so it pays to know what you’re dealing with.

Back then we used our eyeballs more than anything. If you were in VMC, you could just steer around the weather looking at the “radar” picture displayed in your windshield. If the clouds obscured your view, you could fly low and avoid rain shafts along the way. But it often wasn’t that easy. Haze and embedded storms were a big impediment to visual avoidance. It wasn’t like thunderstorms in Arizona that you could see from 100 miles away. You’d be flying in clouds or thick haze, the windshield would suddenly turn black—and boom, you were in it. All of us who flew then got pretty good at making a quick one-eighty before penetrating the heart of the storm. Flight Watch also was a big help, and that service still is available today.

Now, pilots have datalink weather in the cockpit via subscription services or ADS-B. Flight Watch is a resource, and ATC sometimes can provide excellent guidance. Flying from North Carolina back to Maryland one day in a Beechcraft Baron, a wonderful controller gave me some great advice as we approached a line of thunderstorms. I had queried him about where other airplanes were traversing the weather.

“Petersburg, Virginia, is just ahead of you with a courtesy car and a decent restaurant nearby,” he replied. “By the time you get back from eating, all this weather will be through here.” That’s all we needed to hear. And he was right—we flew home in mostly clear skies. I didn’t scare my (future) wife, myself, or put the airplane in harm’s way.

When it comes to datalink, of course, you’ve likely heard that there’s a delay associated with the weather pictures you get. It’s a great tool for getting around areas of weather, but not for picking your way between storms. For that, you need weather radar aboard, and a good one at that. Radar paints a picture of the weather in real time. But there’s a learning curve with radar that pilots must be familiar with, mainly involving the Tilt control, which aims the beam up and down.

But just because you graduate to an airplane that has radar doesn’t mean you can fly in any weather. General aviation airplanes are hobbled by radar systems that use a small dish, usually about 10 to 12 inches in diameter. Because of this, they can’t transmit or receive as much information as radar in larger airplanes. In general, radar in a GA airplane is good for about 40 miles of range. It’s also more prone to shadowing, where a storm cell could absorb all of the radar beam’s energy, effectively hiding storm cells that could be lurking beyond.

An airliner has a comparatively huge dish mounted behind its nose cone, allowing a much larger and powerful radar beam that can snoop out storms 300 miles or so ahead. It also doesn’t shadow storms that may be lurking beyond the one you’re looking at. Keep in mind the size of your dish and quality of your radar system before tangling with storms.

Sferics—lightning detectors such as L3’s Stormscope and Insight’s Strike Finder—are still very valuable items to have in your weather avoidance arsenal, especially if you live in more tropical climates such as Florida. Often, flying airliners into Florida airports, we paint mean-looking blobs of red on our radar—yet aircraft ahead report a smooth ride in heavy rain. The difference is that those red-painted storms aren’t convective at the moment. In those circumstances, sferics devices reinforce the radar picture ahead. If there are no lightning strikes, there shouldn’t be any convection. It should be noted here that most datalink weather services have the option of displaying lightning strikes, for a fee. Keep in mind, though, that the data is delayed just like the radar picture—while sferics will paint the strike immediately.

Of course, the trifecta of weather avoidance gear would be the combination of Nexrad datalink, weather radar, and sferics. Having only one or two in your arsenal doesn’t leave you grounded. You just need to be familiar with the limitations of the equipment and know when to throw in the towel if what looms ahead is beyond your capabilities—or those of your airplane. For years, I flew my family’s Baron around with just a Strike Finder and Flight Watch. I managed to stay out of thunderstorms but did watch the windshield turn black a time or two before making a quick one-eighty. And the airplane certainly got plenty of baths that weather radar or Nexrad could have kept me out of. If I could only have one weather gadget now in a recreational airplane operating in the United States, however, it would be datalink weather because of its superb bang-for-the-buck value.

It goes without saying that all the fancy equipment and techniques mentioned here are not nearly as important as having a pilot with sufficient gray matter between the ears to realize that there are conditions where airplanes simply do not belong. When those conditions are found, it’s time to activate your Plan B, or even Plan C. If the weather is so ugly that you don’t have alternate plans, it’s best to follow the advice that Richmond Approach controller gave me years ago—just take the courtesy car to the restaurant.

Pete Bedell is a pilot for a major airline and co-owner of a Cessna 172 and Beechcraft Baron D55.