Researchers from the National Center for Atmospheric Research in Boulder, Colo., are using an assortment of remote sensors, including a polarimetric radiometer, lidar, radar and weather balloons, in a series of tests aimed at improving knowledge of aircraft icing. As part of the project, NASA's Glenn Research Center flew a Twin Otter aircraft through clouds above New Hampshire's Mount Washington in April. The team will use the sensors to analyze supercooled droplets and ice crystals. The droplets remain liquid until they encounter a surface on which to freeze. Unfortunately for aviators, this surface is frequently an airplane wing. The goal of the Mount Washington research is to improve in-flight ice detection and computer model forecasts.