Author Background

Douglas Boyd Ph.D., holds an adj research Professorship at Embry Riddle aeronautical university (World Wide). He is an active commercial-certificated instrument-rated pilot and has published 28 aviation-related research articles. Douglas chairs the Aerospace Medical Association Safety committee. His research interests focuses on general aviation safety.

Thomas Guinn is a Professor of Meteorology and the chair of the Applied Aviation Sciences Department at Embry-Riddle Aeronautical University. He joined the Embry-Riddle faculty in 2008 after completing a 22-year career in the U.S. Air Force as a weather forecaster. Dr. Guinn received a B.S. in Meteorology from Iowa State University and his M.S. and Ph.D. in Atmospheric Science from Colorado State University. His research interests include aviation meteorology and aviation weather education.


Introduction: Flights of general aviation aircraft in icing conditions pose safety hazards especially since few airplanes are equipped with ice protection systems (FIKI). Herein, we sought to answer the following questions not previously addressed: (i) Has the general aviation icing-related accident rate declined over time? (ii) Which phase(s) of flight lead(s) to the highest fraction of fatal accidents? (iii) Do general aviation pilots adhere to safe practices when operating in forecasted icing?

Methods: Retrospectively, icing-related accidents were per the National Transportation Safety Board database. Prospectively, non-FIKI single-engine airplanes, operating in forecasted icing, were tracked (January–March 2023) using FlightAwareR. Presumptive icing was determined with METARs/modelled Skew-T data. Statistical tests employed Poisson distributions/Pearson chi-square analyses. Results: In a retrospective analysis, despite a nonstatistical (p=0.621) downward trend in icing-related accidents (2000–2019), over half of mishaps were fatal, a fraction unchanged (p=0.842) over the two decades. Loss-of-control represented the terminating event with the highest proportion of fatal outcomes (85%). Accidents involving takeoff-climb ice accretion were overrepresented for fatal outcomes (66%). In a prospective study arm, of 300 non-FIKI flights operating in forecasted icing and tracked in real time, 65% departed or descended/landed (44%) in presumptive icing.

Conclusions: A modest downward trend in icing-related accident rate and an undiminished high fraction of fatal mishaps rationalize focused training of pilots operating non-FIKI aircraft in areas prone to icing. Specifically, two novel observations warrant emphasis: (i) an approximately threefold higher icing-related fatal accident fraction compared with all general aviation accidents and (ii) the high proportion of lethal mishaps due to takeoff-climb ice accretion.