A new safety alert issued by the National Transportation Safety Board points out the many hazards of icing and urges pilots to take counter measures immediately.
As little as one-quarter inch of ice on the leading edge of the wing can be deadly and can increase stall speeds by as much as 40 knots, the safety alert warns. To help identify potential control problems as soon as possible, pilots are urged to limit the use of the autopilot in icing conditions. By automatically correcting for changing flight conditions, the autopilot can mask an impending stall or other ice-related control problems.
Pilots flying aircraft equipped with de-icing boots are urged to activate them as soon as they encounter ice unless their aircraft’s operating handbook specifically says the boots should not be activated.
For more information about icing, check out the AOPA Air Safety Foundation’s cold weather resources page online. There you’ll find links to the Weather Wise: Precipitation and Icing interactive course, as well as numerous publications on icing. Also be sure to review the Winter Flying subject report from the AOPA Pilot Information Center.