Ralf H. Mayer

Estimating operational benefits of aircraft navigation and air traffic control procedures using an integrated aviation modeling and evaluation platform

Complex constraints generally define the performance of air transportation systems. These constraints include aircraft operational characteristics, airline operating procedures, and air traffic control (ATC) requirements. The operational variability that is present in complex air transportation systems and their components typically demands a Monte Carlo approach when modeling system performance metrics. However, the inherent variability is generally not known a priori. This calls for a separate model validation approach that yields estimates of system variability and validates baseline model performance. This paper reports on an integrated aviation modeling platform that was developed for comparing and evaluating proposed aircraft flight operations and ATC procedures. It integrates both an agent-based Monte Carlo modeling environment and a data-driven model validation capability. The capabilities are outlined, the validation approach is described, and examples are presented of performance metrics quantifying operational benefits of air navigation procedures that are currently being implemented at major U.S. airports

Modeling of air traffic arrival operations through agent-based simulation

This paper reports on the development and validation of an agent based simulation model of air traffic control arrival operations. The simulation model includes modeling of both the structure and procedures of air traffic operations. It is thus suitable for evaluating the impacts of shifts in those structures and procedures. Three key operational metrics are introduced which are sensitive to the internal workings of air traffic arrival operations. The simulation model is validated by demonstrating agreement in those key metrics between the simulation and a set of baseline arrival operations radar data. After the simulation model has been shown to reproduce actual operations, select details of the simulation can be altered to incorporate proposed operational changes. The impact of the changes on the computer simulation will offer a prediction of how the operational changes will affect actual operations.

Improving Terminal Operations - Benefits of RNAV Departure Procedures at Dallas-Fort Worth and Hartsfield-Jackson Atlanta International Airports

Incremental implementation of terminal Area Navigation (RNAV) procedures has yielded significant operational benefits at major U.S. airports. Key prerequisites of these benefits are the advanced flight automation systems that are available on the majority of today’s commercial and corporate aircraft as well as the presently achievable conformance of flight operations to the RNAV route structures. Key implementation sites of RNAV procedures include Dallas-Fort Worth (DFW) and Hartsfield-Jackson Atlanta (ATL) International airports. The RNAV Standard Instrument Departure (SID) procedures implemented at these airports have promised and delivered more efficient utilization of available runways and constrained departure airspace by enabling diverging departure operations. This paper investigates the RNAV route conformance currently observed in RNAV departure operations at DFW and ATL and reviews the mechanism that enables operational benefits. It describes the Monte Carlo modeling approach taken to evaluate operational changes, the methodology used to validate model performance with radar data, and presents estimates of departure capacity and delay reduction benefits. The results of the research suggest that capacity gains of about 10 additional departures per hour and runway are possible resulting in significant benefits to operators when RNAV procedure designs enable airports to conduct diverging departure operations. The paper also compares key performance metrics of the model to performance metrics obtained from extensive preand post-implementation operational evaluations. The evaluation results were found to confirm expected operational changes, validate user benefits resulting from diverging RNAV departure operations, and firmly support further terminal procedure implementation at other airports.

Evaluation of RNAV Departure Operations at Dallas Fort-Worth International Airport

On September 6, 2005 the Federal Aviation Administration (FAA) implemented revised area navigation (RNAV) departure procedures at Dallas-Fort Worth International Airport (DFW). The route structure of the procedures was designed to enable diverging departure operations that distribute departure traffic flows over a wider area of DFWs terminal airspace. Operational changes associated with the implementation were found to result in more efficient utilization of available runways and constrained airspace around the airport. This paper documents the results of comprehensive evaluations of observed operational changes. It reviews the design of the departure procedures and evaluates dependencies between DFWs two general implementation objectives of (1) realizing departure efficiency benefits while (2) maintaining the distance flown in terminal airspace. This paper describes the analysis methodology developed to evaluate operational changes using radar data. It presents pre- and post-implementation comparisons of benefit metrics characterizing the distance departing aircraft fly in terminal airspace and the continuity of observed departure climbs. The results show that DFWs gains in departure efficiency were realized without significantly impacting the flight distance and climb continuity of departure operations in DFWs terminal airspace

Benefits and constraints of time-based metering along RNAV STAR routes

The NextGen Integration and Implementation Office of the Federal Aviation Administration has outlined a set of novel operational concepts for improving the efficiency of air traffic operations. In the terminal domain, one proposed operational change is Time-Based Metering (TBM) utilizing Area Navigation (RNAV) Standard Terminal Arrival (STAR) route assignments. The MITRE Corporations Center for Advanced Aviation System Development (CAASD) was tasked to provide benefits and feasibility analysis of these proposed changes and to develop models to test concepts for use in the management and control of air traffic. This paper describes the evaluation of potential benefits and constraints on the feasibility of implementing TBM along RNAV STAR routes. It focuses on computer simulated trial runs of a case study in which time-based metered delivery is implemented at Hartsfield-Jackson Atlanta International airport. This study has yielded two important findings. The first finding is the maximum tolerable variation of actually realized en-route to terminal delivery times from the prescribed schedule times. The second finding is an estimate of the potential reduction in low altitude vectoring in high density airspace.

Evaluation of RNAV Departure Operations at Atlanta Hartsfield -Jackson International Airport

On April 13, 2005 the Federal Aviation Administration (FAA) implemented revised Standard Instrument Departure (SID) procedures at Atlanta HartsfieldJackson International Airport (ATL). The procedures utilize Area Navigation (RNAV) capabilities that enable point-to-point navigation largely independent of ground-based navigational aids, providing greater flexibility in route design and operations. Implementation and usage of RNAV procedures leverages flight automation systems currently available on most Instrument Flight Rules (IFR)operated aircraft in the National Airspace System (NAS). The implementation of RNAV procedures at ATL has delivered increased departure efficiency, i.e. more efficient utilization of available runways and constrained airspace surrounding the airport. This paper outlines the design of ATL’s RNAV departure procedures and the results of comprehensive evaluations of operational data. This paper describes the analysis methodology developed to evaluate operational changes using radar data, and presents preand post-implementation comparisons of several key benefit metrics: departure efficiency, the distance departing aircraft fly in terminal airspace, and the climb continuity of departing aircraft. The results show that ATL realized gains in departure efficiency while reducing the distance aircraft fly in its terminal airspace. The results also indicate that potential exists for further distance benefits in a planned future implementation.

Analysis of RNAV arrival operations with descend via clearances at phoenix airport

On 10 October 2006, two new area navigation (RNAV) arrival procedures for Phoenix Sky Harbor International Airport (PHX) were published which provide vertical guidance in the terminal area. The procedures largely overlay corresponding conventional procedures and established navigation patterns used by air traffic control (ATC). However, the inclusion of vertical guidance and routine ATC issuance of descend via clearances to leverage this guidance was expected to result in more continuous aircraft arrival descents inside the terminal area. More continuous descents enable prolonged flight under reduced engine thrust and associated fuel burn and environmental benefits. The MITRE Corporations Center for Advanced Aviation System Development (CAASD) was tasked by the Federal Aviation Administration (FAA) to assess operational changes associated with the implementation of the new RNAV arrival procedures at PHX and estimate the resulting user benefits. Based on analysis of radar data recorded during eleven days of pre-and post-implementation operations, significant improvements in descent continuities were observed for aircraft descending via the new procedures. The improvements resulted in a 38-percent reduction in the time aircraft remained in level flight at key step-down altitudes in terminal airspace. Fuel burn benefits to users were estimated at

Wind dependent concepts for wake avoidance: a comparative analysis of capacity benefits and implementation risks

0.5 million annually, and resulting reductions in CO2 emissions were estimated at approximately 2500 metric tons annually. In addition to these currently realized benefits, improved participation coupled with procedure optimization efforts promise increased future user benefits.

Concept and Benefits of PBN-Enabled Parallel Approach Operations

The FAA and NASA are jointly embarking on a multiphased research and development program to develop and implement wake vortex avoidance solutions that can safely reduce separations and improve capacity at airports in the NAS. Many options have been proposed by the wake turbulence community and it is necessary to focus research efforts on the most promising solutions. As part of its WakeVAS initiative, NASA has conducted an investigation of the research difficulty and cost for candidate operational enhancements through a Conops evaluation team (CET). This team included participation by stakeholders from many research, system engineering, system development, pilot, and controller organizations. The operational enhancements that were evaluated included wind-dependent concepts for arrivals to closely spaced parallel runways (CSPRs), departures from CSPRs operated as a single runway, arrivals to single runways, and departures from single runways. To complement this work and help provide the information necessary for NASA to focus their research program toward the most promising concepts, MITRE/CAASD performed an analysis of the potential capacity benefit, opportunity for application, and implementation risk for each arrival and departure concept evaluated by the CET. This paper provides an overview of the direction in which NASA research will proceed and the analysis results that help support this decision.

Concept and benefits of a unified departure operation spacing standard

The advent of Required Navigation Performance (RNP) capabilities enabled the development of the Established-on-RNP (EoR) approach concept. Flight validations of the concept are currently being conducted at Denver International Airport (KDEN) to demonstrate the operational viability of independent parallel EoR approaches to widelyspaced runways. The validations complement ongoing studies to determine the acceptability of routine EoR operations from a safety aspect. Broader application of EoR operations and the ability to realize associated benefits throughout the National Airspace System (NAS) largely hinge on aircraft RNP equipage levels and achieved navigational performance to safely support approaches to runways with closer centerline spacing. This paper explores options to leverage Performance-Based Navigation (PBN) capabilities commonly available on modern transport category aircraft to enable NAS-wide use of curved flight paths and same-altitude turns to independent final approaches for landing on parallel runways. Initial findings suggest that leveraging design flexibilities to increase the lateral spacing between turns to angled approach paths may facilitate PBN-based approach applications and enhance operational safety. The paper reviews the separation standards and air traffic control requirements currently applicable to parallel approach operations, presents procedure design concepts that capitalize on PBN-enabled design flexibility, outlines key benefits of associated operational changes, and identifies potential applications.