Aircraft Icing

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Webinar: Icing and Winter Operations – Review the Essentials

September 24, 2010

An invaluable briefing for flight operators wishing to be well prepared for winter flight operations with the latest best practices for de-icing and preventing icing is now available through a National Business Aviation Association (NBAA) Webinar hosted by Dr. Judith Van Zante, icing specialist and aeromechanical engineer with Sierra Lobo, Inc. at NASA Glenn Research Center.

The hour-long interactive session, including Dr. Van Zante's answers to some important questions, provides the latest guidance to supplement current regulatory requirements and flight managers' company policies. For instance, did you know that frozen contaminants similar in size to the grains on medium or coarse sandpaper on a wing can reduce maximum wing lift by 30 percent, or increase lift-induced drag by 40 percent?

Frozen contaminants – including frost, snow, ice and slush – are major hazards, Van Zante explains. To illustrate the magnitude of the risk, her Webinar presentation includes a video simulation of a 2002 accident in which a Bombardier Challenger 604 crashed during takeoff at Birmingham International Airport in the UK. The cause was found to be the result of light frost buildup on the aircraft's wings that was noted by the flight crew during preflight checks but assumed to be within safe range. The crash and fire that ensued resulted in five deaths, including the two pilots.

As Van Zante emphasizes, it is never advisable to assume. "Know that your aircraft is clean" before taxi and takeoff, she says.

In the session, she describes the latest techniques and tools provided by ice protection systems, both for de-icing and anti-icing, and describes the removal and contamination factors that flight operators need to be alert to, and the effects of ice on both the performance degradation and handling qualities of aircraft, using reviews of several scenarios and case studies.

Major types of de-icing and anti-icing fluids are described, including their characteristics of protection, and Holdover Times (HOT), and risks of failure in intense winter conditions.

The NASA research scientist also emphasizes the need to do detailed planning for cold weather flight operations that cover departure, enroute and destination airports, answering such important questions as: whether to hangar the aircraft for protection from frost or frozen precipitation; does the FBO have reliable de/anti-icing services that can handle the aircraft's configuration; and what are the alternate airports/routes to work around weather?

She explains that it is always a good idea to have alternate plans in advance, including best altitudes and re-routes, and alternate approaches to cope with in-flight icing risks.

In addition, Van Zante covers the risks to turbine engines from ice crystal icing that can lead to power loss events such as stall, surge or flameout at altitude, and provides safety resources and recommendations from the National Transportation Safety Board and other aviation experts to assist flight operators in being fully prepared for safe jet operations in cold weather.

For more information about this expert winter operations review, visit