Ground ice has been a contributing factor in many aircraft accidents over the past 25 years. Even small amount of fronts snow, ice, or freezing rain on critical surfaces can create serious flight problems. These include an increase in stall speed, altered flight characteris tics, reduced controllability, incorrect instrument readings, and damage to engines if ice is ingested after it sheds. Even though your aircraft may be certified to fly in known icing conditions, it is not certified for takeoff with ice adhering to the airframe. Any accumulated ice must be removed and the aircraft kept in a clean condition up to and during the takeoff roll. The ultimate responsibility for determining that an aircraft is clean and meets airworthiness requirements rests with the pilot-in-command. If you are one, be aware that at times you may not be able to determine whether your aircraft’s critical control surfaces are free of these contaminants, but you will be held accountable anyway. So, becoming thoroughly familiar with what Type I and Type II fluids can and cannot do for you is very important. FAA’s new documented deicing program requires Part 121 airlines to have training pro grams for employees who apply fluids, to identify which personnel are responsible for what, and to establish standards for implementing the procedures. FAA’s program also requires a statement of what information will be transmitted to the cockpit about what fluid type/concentrations were applied and when it was done. This allows the pilot-in-command to have the necessary information to make a takeoff decision and to be responsible. Ground ice contamination is a result of various forms of precipitation, as well as frost. Snow and freezing fog, drizzle and rain are the precipitation types responsible for ground ic ing. A variety of frost exists meteorologically, but from an aviation standpoint, only two - some and none - are important, and some is too much.4. Which of the following differs from the other three?