Ice formation on aircraft can disrupt the smooth flow of air over the wings and prevent the aircraft from taking off or decrease the pilot's ability to maintain control of the aircraft. Despite a variety of technologies designed to prevent ice from forming on planes, as well as persistent efforts by the FAA to mitigate icing risks, icing remains a serious concern. This statement provides info. on: (1) the extent to which large commercial airplanes have experienced accidents and incidents related to icing and contaminated runways; (2) the efforts of FAA to improve safety in icing and winter weather operating conditions; and (3) the challenges that continue to affect aviation safety in icing and winter weather operating conditions. Charts and tables.

A series of passes on 6 December 1979 through multilayered-supercooled stratiform and stratocumulus clouds by the Air Force Geophysics Laboratory's instrumented C-130E cloud physics research aircraft is used to evaluate a Rosemount Ice Detector. The response of the detector to icing conditions is compared with measurements from a J-W liquid water content meter and the Knollenberg Axial Scattering Spectrometer Probe (ASSP). A procedure to adjust for zero drift of the J-W instrument is developed. Comparison of liquid water measurements from the J-W and from the ASSP indicate that these data are highly correlated and similar in magnitude. A procedure for extracting useful information from the Rosemount Ice detector has been developed. The icing conditions in the cloud systems studied are typical of the range of conditions in winter stratiform clouds. Liquid water (LWC) values of 0.3 g/cu m and median volume diameters of 15 micrometers were most frequently observed. The results of the analysis show that the Rosemount Ice Detector is a sensitive indicator of the fluctuations of liquid water in clouds with LWC not exceeding 0.8 g/cu m -3.

Data on the meteorological parameters pertinent to the aircraft icing problem are so summarized as to give the frequency of occurrence of observed icing situations according to two of the parameters. The summarized data indicate that statistical relations exist between some of the parameters. A method, based upon the collection efficiency of an airfoil and the frequency occurrence of icing situations with various liquid-water contents and mean-effective droplet sizes, is proposed for the selection of design criterions for ice-protection equipment. The method provides a convenient means of calculating the percenteage of icing encounters in which the water collection exceeds the design rate.

Title of supplementary volume: De/anti-icing optimization.

This unique book presents ways to mitigate the disastrous effects of snow/ice accumulation and discusses the mechanisms of new coatings deicing technologies. The strategies currently used to combat ice accumulation problems involve chemical, mechanical or electrical approaches. These are expensive and labor intensive, and the use of chemicals raises serious environmental concerns. The availability of truly icephobic surfaces or coatings will be a big boon in preventing the devastating effects of ice accumulation. Currently, there is tremendous interest in harnessing nanotechnology in rendering surfaces icephobic or in devising icephobic surface materials and coatings, and all signals indicate that such interest will continue unabated in the future. As the key issue regarding icephobic materials or coatings is their durability, much effort is being spent in developing surface materials or coatings which can be effective over a long period. With the tremendous activity in this arena, there is strong hope that in the not too distant future, durable surface materials or coatings will come to fruition. This book contains 20 chapters by subject matter experts and is divided into three parts— Part 1: Fundamentals of Ice Formation and Characterization; Part 2: Ice Adhesion and Its Measurement; and Part 3: Methods to Mitigate Ice Adhesion. The topics covered include: factors influencing the formation, adhesion and friction of ice; ice nucleation on solid surfaces; physics of ice nucleation and growth on a surface; condensation frosting; defrosting properties of structured surfaces; relationship between surface free energy and ice adhesion to surfaces; metrology of ice adhesion; test methods for quantifying ice adhesion strength to surfaces; interlaboratory studies of ice adhesion strength; mechanisms of surface icing and deicing technologies; icephobicities of superhydrophobic surfaces; anti-icing using microstructured surfaces; icephobic surfaces: features and challenges; bio-inspired anti-icing surface materials; durability of anti-icing coatings; durability of icephobic coatings; bio-inspired icephobic coatings; protection from ice accretion on aircraft; and numerical modeling and its application to inflight icing.