Design of an Aircraft Vortex Spacing System for Airport Capacity Improvement

David A. Hinton*, James K. Charnock t, and Donald R. Bagwell _NASA Langley Research CenterHampton, VirginiaAbstract AbbreviationsThe National Aeronautics and Space ATCAdministration (NASA) is addressing airport AVOSScapacity enhancements through the Terminal Area CTASProductivity (TAP) program. Within TAP, the CWReduced Spacing Operations element at the DFWNASA Langley Research Center is developing anAircraft VOrtex Spacing System (AVOSS). EDRAVOSS will integrate the output of several systems FAAto produce weather dependent, dynamic wake ITWSvortex spacing criteria. These systems provide MIAcurrent and predicted weather conditions, models MITof wake vortex transport and decay in theseweather conditions, and real-time feedback of NCEPwake vortex behavior from sensors. The goal ofthe NASA program is to provide the research and NCSUdevelopment to demonstrate an engineering model RASSAVOSS, in real-time operation, at a major airport. SEAA wake vortex system test facility was established SFOat the Dallas-Fort Worth International Airport SODAR(DFW) in 1997 and tested in 1998. Results from TAPoperation of the initial AVOSS system, plus TAPPSadvances in wake vortex prediction and near-termweather forecast models, "nowcast", have been TDWRintegrated into a second-generation system. This TKEAVOSS version is undergoing final checkout inpreparation for a system demonstration in 2000.This paper describes the revised AVOSS systemarchitecture, subsystem enhancements, and initialresults with AVOSS version 2 from a deploymentat DFW in the fall of 1999. *AVOSS Principle InvestigatortAerospace TechnologistSEngineering TechnicianCopyright © 1999 by the American Institute ofAeronautics and Astronautics, Inc. No copyright isasserted in the United States under Title 17, U.S. Code.The Government has a royalty-free license to exerciseall rights under the copyright claimed herein forGovernment purposes. All other rights are reserved bythe copyright owner.Air Traffic ControlAircraft VOrtex Spacing SystemCenter Tracon Automation SystemContinuous WaveDallas-Fort Worth InternationalAirportEddy Dissipation RateFederal Aviation AdministrationIntegrated Terminal Weather SystemMiami International AirportMassachusetts Institute ofTechnologyNational Center for EnvironmentalPredictionNorth Carolina State UniversityRadio Acoustic Sounding SystemSeattle International AirportSan Francisco International AirportSOund Detection and RangingTerminal Area ProductivityTerminal Area Planetary boundarylayer Prediction SystemTerminal Doppler Weather RadarTurbulent Kinetic EnergyAVOSS OverviewThe present NASA development effort is funded bythe Terminal Area Productivity (TAP) program.The goal of the TAP program is to developtechnologies required to allow air traffic levelsduring instrument operations to approach or equallevels presently achievable only during visualoperations. A number of factors lead to areduction in airport capacity in those weatherconditions that preclude the use of visual approachprocedures. These factors include a reduction inthe number of available runways and thelongitudinal wake turbulence separationconstraints used by Air Traffic Control (ATC). These wake constraints (table 1) evolved over timeto prevent wake encounters in weather conditionsmost conducive to long-lived wakes, and areunnecessarily large in weather domains that lead