Atmospheric icing
Atmospheric icing occurs when water droplets in the atmosphere freeze on objects they contact. This can be extremely dangerous to aircraft, as the built-up ice changes the aerodynamics of the flight surfaces, which can increase the risk of a subsequent stalling of the airfoil. For this reason, ice protection systems are often considered critical components of flight, and aircraft are often deiced prior to take-off in icy environments.
Not all water freezes at 0 °C or 32 °F. Liquid water below this temperature is called supercooled, and such supercooled droplets cause the icing problems on aircraft. Below −20 °C (−4 °F), icing is rare because clouds at these temperatures usually consist of ice particles rather than supercooled water droplets. Below −42 °C (−43.6 °F), supercooled water cannot exist, therefore icing is impossible[citation needed].
Icing also occurs on towers, wind turbines, boats, oil rigs, trees and other objects exposed to low temperatures and water droplets.
Aircraft incidents
A number of aircraft crashes have been caused by ice. In other incidents icing was a contributory factor.
See also
References
FAA (U.S.) Advisory Circular 20-113: Pilot Precautions and Procedures to be taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems
FAA (U.S.) Advisory Circular 20-117: Hazards Following Ground Deicing and Ground Operations in Conditions Conducive to Aircraft Icing
FAA (U.S.) Advisory Circular 20-147: Turbojet, Turboprop, and Turbofan Engine Induction System Icing and Ice Ingestion
Wind Energy in Cold Climates: Icing on wind turbines
External links
- Airline Regulators Grapple With Engine-Shutdown Peril WSJ April 7, 2008
- Supercooled liquid water and airframe icing
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