P&E WX WATCH A PENCIL HELPS illustrate the relative size of the ice droplets. 1,000 microns =.04 in 500 microns 200 microns 50 Freezing rain Freezing drizzle Roselawn estimated droplet diameter Max continuous (stratus) 40 15 Max Intermittent (cumulus) FAR Part 25, Appendix C droplet diameters Deadly droplets Discovering large-droplet icing—the hard way BY THOMAS A. HORNE I WAS GOING OVER some weather docu- EXPERT SPOT ments the other day and came across an icing accident that will go down in history as one of the most notorious. It was a true landmark accident, and it occurred at 3:59 p.m. CST on October 31, 1994, at Roselawn, Indiana (“Safety Pilot Landmark Accident: CLASSIFICATION OF ICE An Inconvenient Departure,” January 2007 AOPA Pilot). The fallout from that accident still has repercussions today, and still gives us many valuable lessons. But enough time has passed that many pilots aware of it at the time have forgotten many details, and PHASE OF FLIGHT 23% Glaze 14% Rime 63% Mixed 17% Approach 4% Takeoff 21% Climb 25% Cruise 33% Descent Illustration from John P. Dow Sr.’s “Unusual Icing” poll 88 | AOPA PILOT November 2012http://www.cfirenewalonline.com http://www.cfirenewalonline.com