Sunday, November 11, 2007

Thunderstorms building at altitude.

Airplane Owners and Pilots Association (of which I am a member), has many resources for pilots online. For example: AOPA Air Safety Foundation Thunderstorm Avoidance Minicourse.

Thunderstorm clouds can be easy for VFR pilots to spot, but IFR pilots flying in the soup often rely on air traffic control (ATC) to route them around the severe weather.
Communication is key when working with ATC, as the AOPA Air Safety Foundation explains in its new four-minute minicourse, Avoiding Thunderstorms.

Avoiding Thunderstorms contains actual ATC transmissions between controllers and a pilot who flew into a Level 6 thunderstorm with tragic results. The audio dramatically illustrates the need for clear pilot-ATC communication and understanding of radar services provided.

The course advises pilots to verify with each controller they are handed off to exactly what services they will receive. This can help minimize the chances of a misunderstanding.

You'll also learn about ATC services, the enhancements in controllers' weather radar displays, and the importance of giving pilot reports. A list of weather- and ATC-related subjects at the end of the course leads you to more information. http://www.aopa.org/whatsnew/newsitems/2005/050701storms.html

You can also read one of their Safety Advisor Publications, 8 pages long, at http://www.aopa.org/asf/publications/sa26.pdf, which includes:

What if the worst happens and you find yourself in the belly of the beast? You can increase your chances of surviving a thunderstorm encounter by taking a few, simple steps. First, throttle back and slow down before getting into severe turbulence.

Aiming for maneuvering speed (Va) can help protect the airframe from being overstressed by the violent air currents of a thunderstorm, but don’t try to “chase” a particular airspeed. As the airspeed needle swings wildly, you’ll be doing well to hold the average of the swings somewhere near the published Va.


The second step is to make the airplane as aerodynamically “dirty” as possible without lowering the flaps (which usually reduces structural strength). In complex aircraft, extend the landing gear. The added drag reduces the potential for rapid acceleration and, in turn, the potential for loss of control, or excessive airframe loads.

Finally, maintain a very loose straight-and-level flight attitude and forget about holding a particular heading, altitude or airspeed. Trying to exercise precise aircraft
control in a thunderstorm is both futile and counterproductive: It’s impossible, and it greatly increases the odds of damaging the airframe.

Thanks for checking out the Girls With Wings blog.

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