The In-Cloud ICing and Large-drop Experiment (ICICLE) mission flew into precipitation and ice-prone clouds in the western Great Lakes region for over 100 hours in winter 2019. Over a 6-week period, a team of researchers from the National Research Council of Canada (NRC) and Environment and Climate Change Canada flew 30 data-collecting flights in one of North America's most ice-prone areas, seeking out supercooled large drops–freezing rain and freezing drizzle – and collecting information about the environments in which they occur.
Aircraft icing is a hazard that can impact flight safety, altering the delicate balance of aerodynamics and lift. Most pilots do their best to avoid the conditions that cause icing, but researchers at the NRC have been heading straight in-to them.
A team of NRC researchers equipped the Convair-580 aircraft with more than 40 sensors that measured cloud microphysics, temperature, relative humidity, aerosol concentration, size and composition, and other environmental properties. By using satellite data, weather forecasting models, and communicating with researchers on the ground, research pilots led by NRC Test Pilot Anthony Brown were able to precisely navigate the aircraft into various types of icing and non-icing environments.
The ICICLE study was funded through the Federal Aviation Administration’s (FAA) Aviation Weather Research Program and operated out of Rockford, Illinois. The NRC’s Convair-580 used on-board radar to capture the full vertical structure of clouds along its flight path – from near-surface level through to the top of clouds. It recorded extensive measurements of cloud microphysics, cataloguing moisture and particle size and concentration. Airborne light detection and ranging (LiDAR) and NRC dual-frequency airborne radars (NAWX) were used to locate supercooled large drops, in order to better understand the role they play in ice formation.
International co-operation is a cornerstone of maintaining the exceptional safety record of air travel. The data collected by the ICICLE research project will help improve the industry's ability to anticipate icing conditions – and make aviation safer for all.
The ICICLE study aims to reduce icing-related accidents by improving the ability to recognize and anticipate the conditions that may pose a safety risk in aviation. It will also help improve a pilot's ability to interpret real-time data from aircraft sensors and recognize the conditions that will lead to icing in real time.
Data on particle size and concentration will also help improve atmospheric modelling. This will enable forecasters to more precisely predict when and where icing conditions will occur, and allow flights to be rerouted to safer airspace. The ICICLE study’s lead researcher, Dr. Mengistu Wolde from the NRC, envisions that data collected during the project will be used in comprehensive studies of icing conditions for decades to come.