AOPA Pilot Magazine - July 2011 - 30

SAFETYPILOT

BY BRUCE LANDSBERG
PRESIDENT, AOPA FOUNDATION

In-cockpit weather

ne of the biggest safety advancements for light general aviation aircraft has been the availability of weather information datalinked into

Despite having all of the gear, it doesn’t make unflyable weather flyable.

Today, with Nexrad in the cockpit, the workload is lower and a picture is worth at least 1,000 words. Flight Watch is essential if you’re not equipped for an in-cockpit view but is clearly from the last century. After the privilege of flying datalinkedequipped aircraft since the beginning it would be hard for me to give it up. There is a cost to hardware, with a subscription required in some cases, so if you’re not doing a lot of cross-country flying there’s little reason to invest. However, if the aircraft our cockpits via satellite. No matter whether it’s a is used regularly for transportation the rewards are portable or panel-mounted device, the ability to significant. Like all tools, datalink has to be used AOPA Foundation President Bruce get TAFs, METARS, and—most important—Nexrad intelligently and despite all the marketing promises, Landsberg is an precipitation mosaics has been a huge step forward. there is interpretation, limitation, and nuance. active pilot with It allows us to take trips that otherwise would have In the early 1990s, an FAA associate administrator more than 6,000 been impossible or much more uncertain. was dead set against the idea of providing Nexrad hours. Step back with me a few decades to the bad old pictures because pilots would use the information days before Nexrad was in the cockpit. I was flying tactically to maneuver around storms. I mentioned a Cessna T210 back to Wichita from the East Coast. An active to the administrator that airborne weather radar had occasionfront extended almost the length of the Mississippi Valley. We’d ally been misinterpreted but we certainly wouldn’t give that up. refueled in Mount Vernon, Illinois; filed IFR; and were looking Irrelevant! Catastrophic carnage was predicted, but fortunately at an increasingly angry western sky. ATC wasn’t able to pro- it hasn’t worked out that way. A few datalink-equipped aircraft vide too much help so it was off frequency to Flight Watch for have had weather mishaps but thousands more trips were coma strategic view. pleted in greater safety and confidence. Why not use datalink close in to convective cells? Start with latency. That’s a technical term that simply means the time delay from when the radar scans the storm and the picture appears in your cockpit. It can be a little as a minute or two to or as long as 10 to 12 minutes, although this is unusual. In slow-moving or fairly static weather this is not an issue but in powerful systems, where there can be explosive growth and cells may be moving at 40 to 50 knots, what you see on a 10-minute- old display is not at all what you get. A strong cell moving at Flight Watch can give you a good picture but there are two 40 knots will have moved about four miles in six minutes—not downsides: the information is perishable, as you’ll see in a that far. But if it’s faster or the delay is longer. Watch out! moment, and when there’s real weather to deal with the party Two key points: Maintain at least 20 miles from any strong line on 122.0 MHz can get mighty busy. We’ve all faced the cells, preferably upwind. That means the hole between them weather version of Armageddon 50 miles ahead and needing must be at least 40 miles wide and, secondly, understand the information right now while some jet type at Flight Level 350 general nature of the weather system in which you’re flying. is checking out a sun-filled forecast for West Palm two hours A warm front will have different characteristics than a strong downstream. ATC usually gives us three minutes and then you’d cold front, different from a tropical system, or scattered air mass better be back on frequency. storms. They all have their personalities and while they’re all The situation was “active” but a southern deviation of about bad, some are much nastier than others. 70 miles was recommended. I returned to Center frequency I’ve been reminded on several occasions that despite havbut, out of morbid curiosity, decided to monitor Flight Watch ing all of the gear, it doesn’t make unflyable weather flyable, to see who else was going to get bad news. About 10 minutes and sometimes there’s temptation to cut corners. If you need a later, the Flight Watch advisor called me in the blind to report little more motivation, remember thunderstorms release energy that the southern hole had closed up solid and a northerly route levels that exceed nuclear weapons. The tornadic spring of 2011 over St. Louis was much the better deal. Glad I’d been listen- is a reminder of the power. ing, so we reversed course and penetrated the front with only a I could go on for pages on this topic but strongly recommend slight bouncing and light rain. It worked but wasn’t particularly you take the Air Safety Institute’s new online course available elegant by today’s standards. later this summer. 30 • JULY 2011

AOPA PILOT •

AOPA Pilot Magazine - July 2011

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