Major study of winter storms and aircraft icing

Citation

(2004), "Major study of winter storms and aircraft icing", Aircraft Engineering and Aerospace Technology, Vol. 76 No. 2. https://doi.org/10.1108/aeat.2004.12776bab.007

Major study of winter storms and aircraft icing

Major study of winter storms and aircraft icing

Keywords: Safety, Aircraft, Weather

A major North American study aimed at better understanding of aircraft icing and hazardous winter weather and led by the National Research Council Institute for Aerospace Research (NRC-IAR), Environment Canada's Meteorological Service (MSC) and NASA's Glenn Research Center (NASA-GRC) has recently been carried out. The $3 million Alliance Icing Research Study (AIRS II) focused on freezing rain and other severe winter weather, and was designed to improve air traffic safety through better forecasting and detection of winter weather hazards to aircraft. More than 50 researchers from four countries participated in AIRS II, which took place in Ottawa, Mirabel, Eastern Ontario and Southern Quebec areas, for over a 4 month period.

Aircraft icing, which can occur when airplanes encounter freezing precipitation or cloud droplets with temperatures colder than 0°C, either on the ground or in flight, can be a serious safety hazard. In the US, aircraft icing contributes to some 30 deaths, 14 injuries, and $96 million in personal injury and aircraft damage each year. Icing is also a significant concern for aviation in Canada, particularly in the winter months when icing conditions are frequently encountered. Development of real- time icing detection/warning systems at airports could help mitigate icing related incidents and accidents. Ultimately, this study will improve Environment Canada's ability to detect and forecast hazardous winter weather conditions such as freezing precipitation, icing, winds and snow in the airspace surrounding an airport (Plate 5).

Plate 5 Canada's National Research Council's Convair 580 (left), together with NASA's DHC-6 Twin Otter are two of five aircraft conducting airborne ice and water research during the winter 2003/4 season. The aircraft will collect and analyze samples during storms to better forecast weather patterns for the enhancement of flight safety. The $3 million project includes researchers from five countries, Canada and USA among them

The major fieldwork took place from November 2003 to February 2004. When a winter storm developed over Montreal, five research planes (including NRC's Convair 580 and NASA-GRC's Twin Otter) (Plate 6) set out from airports in Ottawa Ontario, Cleveland Ohio, and Bangor Maine. They converged over the Montreal area, to collect data on the storm at different heights in the atmosphere. Over 65 flights took place. Four of the aircrafts were equipped to make in situ measurements of the environmental conditions; three were instrumented to make remote sensed observations; and two were capable of assessing performance effects associated with ice accumulation on exposed aircraft surfaces. An array of 25 ground-based instruments at Mirabel airport provided extensive information on the vertical structure and time evolution of the storms as they pass over Mirabel. The in situ measurements are being used to validate the capabilities of the ground-based instruments for remotely detecting hazardous environmental conditions.

Plate 6 Underwing probes aboard the NRC's Convair 580 collect images of cloud water and ice particles

The Montreal area was chosen because of its high frequency of freezing precipitation (drizzle or rain), and considering the large amount of air traffic around the Great Lakes, because it represents high air traffic region. The Montreal/ Ottawa area can receive up to 75 h of freezing precipitation each year. (In North America, only eastern Newfoundland exceeds this amount, where up to 150 h of freezing precipitation can occur annually.) Other Canadian partners included Transport Canada, Department of National Defense, Nation Search and Rescue Secretariat, Communications Research Centre, McGill University, and Trent University. Major US partners include the National Science Foundation, the Nation Oceanographic and Atmospheric Administration, the National Center for Atmospheric Research and the Federal Aviation Administration, as well as many university researchers. Two European national weather service partners (Britain and France), also joined the study. AIRS II builds on an earlier study that took place in the same geographic region during the winter of 1999/ 2000. Web site: www.msc.ec.gc.ca/research/airs

Details available from: NRC Institute for Aerospace Research. Tel: +1 613-991-5738; E-mail: michelle.gagnon@nrc-cnrc.gc.ca; Web site: www.nrcaerospace.com