Every winter season the pilot groups at most airlines are send safety reminders on special winter operations. Every season has it's unique challenges, but there's nothing like winter. There's slippery runways, nor easters, gale force winds & equipment that wont start because of the cold. However, today I will talk to you about the challenges of deicing. Ice, & snow on airplanes don't mix. The FAA have a little reminder to pilots that there's no such thing as a little ice. Ice, & snow builds up on the wing & tail in flight, or on the ground & it can cause decrease in lift. In flight, the modern airliner handles icing easily with anti-ice & deice equipment such as wing deice, pneumatic wing boots, fuel heat, windshield heat, & pitot heat. However, on the ground you must be sure the airplane is clean of any ice, snow, or frost that may have accumulated overnight.  In any case the flight crew will make a decision on which type of deice fluid to use. There are 3 main types. Type 1, 2, & 4. Type 1 fluid is unique because it's only used as a deice removal. In other words, it will not prevent any future accumulation. Type 2 & 4 is used as anti ice fluid. It prevents accumulation for an extended period of time. Type 2 ,& 4 is mixed with alcohol & is applied heated. Type 4 is the best because it usually last around 40 minutes. Which fluid you use depends on ground conditions. If It  snowed overnight, & stopped in the morning with the skies turning clear then I might just used only type 1. However, if you plan to depart in the middle of rush hour at JFk with a chance of snow still falling then most crews would prefer type 1 & 4. The deicing fluid looks kind of greenish if you look over the wing. It's also designed to shear off the wing as the airplane accelerates in speed. For more information on the deicing process there is a great video below.

http://www.youtube.com/watch?v=apWHdd1vmPI