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6 Table 1. Survey response rate by inclusion source. Persons in Responses Response Inclusion Source Focus Group Received Rate APS Contacts 24 14 58% ACRP Panel Members 13 6 46% Total 37 20 54% recommended for future study. This model, used for ranking ids, thus reducing environmental impact while maintaining of alternatives, is a systematic formalized procedure for solv- or enhancing aircraft safety. The nature of the potential ing complex decision problems. improvements generally included: Following the compilation of potential de/anti-icing opti- mization technologies and procedures, a list of analytical crite- Procedures that may already be instituted by certain oper- ria for evaluating the usefulness of the selected technologies and ators, but which would offer value if applied on a wider procedures was developed. The Binary Decision Analysis Model scale (example: spot deicing for frost); was then employed to assign a weight to each of the analyti- Procedures that could be instituted, already having regula- cal criteria. This process compared each combination of two tory approval (example: application of dilutions of Type IV criteria and determined which of the two was more important. fluids versus full strength); The more important criterion of each pair is then given the Procedures that would require regulatory approval (exam- value of one, and the other is given a value of zero. At the com- ple: reduced fluid freeze-point buffer for first-step deicing pletion of the exercise, the values are totaled for each criterion, fluid and hot water deicing); and and a percentage is calculated based on the total number of pairs Application of new technologies (either proven or in possible. This exercise with seven selected criteria produced development). 21 pairs for comparison. An initial, internal weighting of the analytical criteria was Preliminary List of De/Anti-Icing made to select technologies and procedures for further research. Optimization Technologies and Procedures This selection was later reinforced by criteria weights deter- mined by the focus group as part of the survey described earlier. The review of technical reports; regulatory, government, and industry documentation; and applicable patents pro- duced the following list of 34 potential de/anti-icing opti- Findings and Applications mization technologies and procedures: Aircraft De/Anti-Icing Optimization Technologies and Procedures 1. Reduction of fluid buffer for deicing-only conditions. 2. Introduction of larger negative freeze-point buffer for The objective of the literature review was to develop a list first-step deicing fluid, enabling use of hot water for deic- of potential means for optimizing the use of de/anti-icing flu- ing at ambient temperatures lower than 26.6F (-3C). Table 2. Survey response rate by interest group. Persons in Responses Response Interest Group Focus Group Received Rate Air Carriers 10 6 60% Airframe Manufacturers 1 1 100% Airport Authorities 4 1 25% Deicing Equipment Manufacturers 1 1 100% Deicing Service Providers 4 2 50% Fluid Manufacturers 3 2 67% Regulators 7 5 71% Other 7 2 29% Total 37 20 54%