Enhanced AEDT Modeling of Aircraft Arrival and Departure Profiles, Volume 1: Guidance (2018)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

  Page 4   1 Introduction Modeling of airport-related noise and air quality impacts began over 40 years ago. Motivated by the National Environmental Policy Act of 1970, and enabled by emerging computer technology, the Federal Aviation Administration (FAA) first created the Integrated Noise Model (INM) in 1976. At that time, the focus of airport noise analysis was on the impacts of departing flights on communities near an airport’s boundary, which were dominated by the use of low bypass ratio engines. In the intervening decades, drastic technological improvements to aircraft engines have led to lower noise and air emissions on a per-flight basis. At the same time, the numbers of operations have generally increased at airports, and NextGen-related changes to navigation technology and flight procedures have introduced noise and emissions impacts to new areas. In 2015, FAA replaced the INM and its other “legacy” environmental models with a single new model that addresses both noise and emissions – the Aviation Environmental Design Tool (AEDT). This new model allows for the simultaneous computation of noise, emissions, and fuel burn as a result of aircraft operations. Yet, some of the data that are built into AEDT, representing the flight performance of aircraft during approach and departure, are developed by aircraft manufacturers following guidelines from four decades ago. With the minimal resources (data and expertise) required to use AEDT, modelers can achieve nominally realistic aircraft performance results. However, in order to make the best use of AEDT, modelers need to capture the real-world performance of aircraft in the airspace surrounding an airport. Doing so with AEDT typically requires either (a) rigorous technical analysis of large datasets to define flight profiles, or (b) extensive aircraft operator and FAA coordination to define customized performance profiles. A gap exists in which environmental modelers, with limited resources and expertise, need to accurately compute the noise and emissions impacts of airport projects – covering a broad area surrounding an airport. The purpose of ACRP Project 02-55, “Enhanced AEDT Modeling of Aircraft Arrival and Departure Profiles,” is to supplement the data and functionality built into AEDT with additional flight profiles and profile modeling methods. The additional profiles and methods are aimed at reducing the burden on the user while enabling a more accurate estimation of noise, emissions, and fuel burn. By better matching real-world flight trajectories in three dimensions, the resulting noise and emissions results will better reflect actual environmental impacts. This Guidance Document was developed to provide users of AEDT – from novices to experienced users – with an easy-to-access guide on the varying approaches to profile modeling, including when and how to use ACRP 02-55 tools and data to support airport environmental studies. Within the context of this ACRP project, the focus was placed on single- airport environmental analysis (e.g., NEPA, 14 CFR Part 150, Master Planning, etc.). Following this introduction section, the Guidance Document contains the following sections: The FAA’s Aviation Environmental Design Tool (AEDT) is a software tool that models aircraft flight performance to compute noise, emissions, and fuel burn. AEDT is used for many types of aviation environmental analyses, from single- airport studies to assessments of multi-airport systems and even nationwide and global studies.

  Page 5   Section 2 – Available Modeling Methods: A description of the array of profile modeling techniques that existed before AEDT, that are new to AEDT, and that are provided by ACRP 02- 55. Section 3 – Selection of Modeling Method Overview: A guideline for AEDT users to select the appropriate profile modeling method based on their unique situation and the needs versus constraints of the environmental study at hand. Section 4 – Modeling Process Details: A step-by-step walk through of the process including trajectory analysis, strategy development, examples of how to create target trajectories from external data, and a worked example for one arrival and one departure flight including AEDT flight profile and environmental metric outputs Section 5 – Interpretation of Results: A discussion on how users should review the flight performance computed by AEDT to ensure reasonableness of the model’s outputs. Section 6 – Conclusion: A high-level summary of the document with overall conclusions. To further assist the reader with the use of the Guidance Document, several key terms are defined below in Table 7. Table 1. Key Terms Used in this Document Term Definition Trajectory A four-dimensional description of an aircraft’s path through space, generally using latitude, longitude, altitude, and speed or time. Target Trajectory (Input Track) A trajectory defined via external data sources that a user wishes to represent within AEDT via a flight profile. Flight Procedure A description, as a series of procedure steps (i.e., takeoff, accelerate, climb, descend, level, etc.), of the behavior of an aircraft as it flies. Default (or Standard) Procedure Flight procedures that are included in the AEDT model and are based upon manufacturer-provided aircraft performance characteristics. Flight Profile The altitude, speed, and engine thrust output defined at several points along an aircraft’s trajectory when approaching or departing from an airport. In this document, only altitudes from ground level to 10,000 feet are addressed. In the context of this document, flight profiles are often calculated using flight procedures. Ground Track A two-dimensional representation of the path an aircraft takes over the ground, typically defined as a series of points at varying latitude and longitude. Stage Length A classification of the trip distance (from origin to destination airport) that a departing flight will travel. Each stage length is associated with a distance range and aircraft-specific takeoff weight. Level-off A segment of a flight profile in which an aircraft maintains a constant altitude (typically during descent, and at the direction of air traffic control). Reduced Thrust For departing aircraft during takeoff and climb, pilots may use less than the maximum available engine thrust. This practice varies depending on the aircraft, airline, airport, runway, and atmospheric conditions. Terminal Area The 3-dimensional airspace surrounding an airport (typically a