Improving the accuracy of airport emissions inventories using disparate datasets

Environmental regulations require airports to report air quality emissions inventories (i.e., tons emitted) for aircraft emissions such as carbon oxides (COx) and nitrogen oxides (NOx). Traditional methods for emission inventory calculations yield over-estimated inventories due an assumption of the use of maximum takeoff thrust settings for all departures. To reduce costs, airlines use “reduced” thrust settings (such as derated or flex temperature thrust settings) that can be up to 25% lower than the maximum takeoff thrust setting. Thrust data for each flight operation are not readily available to those responsible for the emission inventory. This article describes an approach to estimate the actual takeoff thrust for each flight operation using algorithms that combine radar surveillance track data, weather data, and standardized aircraft performance models. A case study for flights from Chicago's O’Hare airport exhibited an average takeoff thrust of 86% of maximum takeoff thrust (within 4% of the average for actual takeoff thrust settings). The implications and limitations of this method are discussed.