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The following stories from the August 14, 2009, edition of AOPA ePilot were provided to AOPA members who expressed an interest in the particular subject areas. Any AOPA member can receive information tailored to their areas of interest by updating their preferences online.


Concealed convectives

The Aug. 7 Training Tip discussed differences between cloudless weather and clear weather and stressed staying alert for the hazard of unexpected restricted visibility in stable air masses. Those hazy conditions might also mask indications of even greater challenges ahead. Air mass thunderstorms developing as a result of surface heating may lie in wait along the route of flight, obscured from view. The AOPA Air Safety Foundation’s Safety Advisor WeatherWise explains that air mass thunderstorms usually occur “on summer afternoons as a result of daytime heating. Usually isolated; you may be able to maneuver around them.” But you have to be able to see them first.


The approach of a fast-moving cold front that marks the boundary of the next large air mass to move into the region usually can be spotted from a distance because of the cloud forms it produces. But that hazard, too, could be concealed. “Prior to the passage of a typical cold front, cirriform or towering cumulus clouds are present, and cumulonimbus clouds are possible. Rain showers and haze are possible due to the rapid development of clouds,” explains Chapter 10 of the Pilot’s Handbook of Aeronautical Knowledge . Keep checking on the weather, especially any pireps or convective sigmets (the topic of the July 24 Training Tip.)


A related caution: Don’t misjudge the clouds you can see on a hazy day. “Popcorn” cumulus clouds are one name given to fair-weather clouds that sprout when solar heating stirs up a stable air mass. They’re not usually cause for concern. But too much popcorn could be hazardous to your health. That was the lesson of one pilot’s “Never Again” encounter with seemingly innocent popcorn cumulus clouds that lived long and prospered one August afternoon in the Midwest.


How bad did that day’s weather become? “That night at a motel in Kankakee, we saw television news reports of devastating tornadoes in Indiana and Illinois that had occurred about the time that we were in the air and about 15 miles east of where we had been,” the pilot wrote of his memorable flight. Let his firsthand experience team up with your weather knowledge to keep you safe in summer’s haze.

TRAINING PRODUCTS offers visual aids for unfamiliar airports

For pilots who want to know as much about an unfamiliar airport as possible before they launch, a new Web site aims to provide visual tools such as pattern videos, reporting point photos, and chart snippets.’s yearly membership fee of $15 provides access to airport data and diagrams, communications information, runway conditions, and current weather. The home page lets users “test fly” one of three California airports to see what’s offered. For more information, see the Web site.


Note: Products listed have not been evaluated by ePilot editors unless otherwise noted. AOPA assumes no responsibility for products or services listed or for claims or actions by manufacturers or vendors.


Question: What is the Airport Watch program all about, and how can I do my part?


Answer: AOPA has partnered with the Transportation Security Administration to develop a nationwide Airport Watch program that uses the more than 600,000 pilots in the United States as eyes and ears to observe and report suspicious activity. Airport Watch includes warning signs for airports, informational literature, and a training video to teach pilots and airport employees how to enhance security at their airports. Read more about the program and how to participate on AOPA Online.


Got a question for our technical services staff? E-mail to [email protected] or call the Pilot Information Center, 800/872-2672. Don't forget the online archive of "Final Exam" questions and answers, searchable by keyword or topic.

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