It's that time of year again. Frost, snow, and ice are in the forecast, and pilots need to know how to handle these hazards. The AOPA Air Safety Foundation's new Safety Brief - Cold Facts: Wing Contamination - gives pilots a quick lesson on the effects of wintry wing contaminants and what to do about them.
The brief notes that in the past 10 years, there have been more than 30 general aviation takeoff accidents caused by snow, frost, or ice on the wing. The issue has caught the attention of the NTSB as well. Last week it issued an unusual " alert to pilots" advising that any frost or ice on the upper wing surface could be hazardous for takeoff. The NTSB recommended a "visual and tactile" wing inspection, noting that frost or ice sufficient to cause aerodynamic performance problems might not be visible to the eye and could be detected only by touching the rough surface.
The AOPA Air Safety Foundation's Aircraft Icing Safety Advisor explains that frost or ice no thicker or rougher than a piece of coarse sandpaper can reduce lift by 30 percent and increase drag up to 40 percent.
"That's a performance penalty that could prevent many light GA aircraft from ever getting airborne," said Bruce Landsberg, AOPA Air Safety Foundation executive director, "and if you did manage to get in the air, you'd likely encounter a much higher stall speed. And if the frost isn't evenly distributed across the wing, there could be asymmetrical stalls on the wing, leading to roll control problems."
An Air Safety Foundation study of general aviation accidents found that 8 percent of fatal icing accidents were due to ground accumulation of ice, snow, or frost on the wings. Icing accidents represent 12 percent of all weather-related fatal accidents.
The AOPA Air Safety Foundation has a wide range of resources to help you avoid becoming a statistic. A recent video produced jointly by the Air Safety Foundation, the FAA's Flight Safety Research Section, and the Icing Branch of NASA's Glenn Research Center focuses on "Icing for General Aviation Pilots." You can view the 55-minute video online (broadband connection recommended) or purchase the DVD for $5 plus shipping through Sporty's Pilot Shop. The video includes an in-depth look at tail ice, and in-flight footage and interviews with NASA pilots explain recovery techniques that could save your life.
Pilots might also checkout the AOPA Air Safety Foundation's online icing quiz, and the Aircraft Deicing and Anti-icing Equipment Safety Advisor .
January 3, 2005