FTA specializes in the application of quantitative techniques to air transportation problems, and we have gained extensive experience in the design and application of aviation models.
  • Real-Time Decision Support Systems:  FTA has developed real-time decision support systems such as the Enhanced Preferential Runway Advisory System (ENPRAS) which is currently operating at Boston Logan International Airport. 
  • FTA Analysis Tools and Models:  FTA has developed a set of tools for evaluating a wide-range of airport and airline issues.  We have developed both simulation and analytical models for evaluating airspace, runway, taxiway, and terminal operations, as well as analysis tools for airline issues such as network, fleet, and schedule optimization.  

  • Third-Party Tools and Models: In addition to our own in-house models, FTA has experience with a number of third-party analysis tools such as SIMMOD, TAAM, the Airport Machine, INM, and others.

In addition to the short model summaries below, detailed descriptions of some of FTA's most frequently-used models are available.  These descriptions are available for the following models:

ENPRAS        DELAYSIM        FLAPS        TASIM        TAXSIM 


Real-Time Decision Support Tools

Enhanced Preferential Runway Advisory System (ENPRAS): FTA developed and implemented ENPRAS to assist the FAA in meeting the goals of Logan's unique runway use program. ENPRAS records historical runway use and, based on community defined noise goals, provides recommended runway configurations that will best meet both near and long-term noise goals. Recommendations are based on projected demand, weather, and historical runway use. ENPRAS has recently been modified to interface directly with the Systems Atlanta Information Dissemination System (SA-IDS4). 

FTA Analysis Tools and Models

Delay Simulation (DELAYSIM): DELAYSIM is a unique FTA model used to simulate air traffic controller runway selection patterns.  The model provides an analysis of total annual delay, delay by weather condition, delays by month, and runway use. DELAYSIM simulates the selection of active runways and their operation for any given period. Output includes runway configuration utilization statistics showing the annual percentage use of each configuration. The selection of runways is based on a logical process constrained by both operational and environmental factors. ATC workload factors are also considered as they may influence configuration selection. For example, the model does not allow changes in the runway configuration during an ATC shift change. DELAYSIM has been used on numerous projects including studies at Amsterdam Schiphol, the Massachusetts Port Authority's recent Logan Airside Improvements Planning Project (LAIPP), and the Sydney Kingsford-Smith modeling project.
Flexible Airport Simulation (FLAPS): FLAPS is a stochastic event-driven simulation that models aircraft operations from the terminal entry fix to the gate area, and from the gate area to the departure fix. It is used to provide measurements of runway capacity, especially in the case of complex runway configurations. The model includes detailed representations of the three primary factors that affect airport runway capacity: 1) runway layout and availability, 2) aircraft characteristics and mix, and 3) air traffic control operating procedures. FLAPS has been implemented world-wide including projects in Australia, Amsterdam, St. Louis, and Boston.
Terminal Airspace Simulation (TASIM): TASIM is a fast-time stochastic simulation developed by FTA to test various ATC airspace design and operation strategies, including those that require navigation and surveillance systems which may not be in use, such as MLS or GPS. The simulation facility can model an arbitrarily large segment of airspace, comprising numerous airports, and handle any number or type of aircraft. The user need supply only environment-specific information (location and type of navigation aids, desired aircraft mix, wind information, etc.). TASIM has been applied by FTA for projects with the United States Navy and the Ministry of Communications and Transportation (MOTC) of the Republic of China (Taiwan).  FTA has recently improved the model graphics to generate not only the original ATC radar-screen display, but also an airspace animation which can be used to present the airspace design to the public. 
Taxiway Simulation (TAXSIM): TAXSIM is a computer simulation of the flow of aircraft through the runway and taxiway network of an airport. The simulator uses a discrete event architecture that models the activity of each aircraft using the airport for a selected period of time. TAXSIM provides a convenient tool for airport planners to evaluate the effects of taxiway layout, aircraft mix, gate assignments, and other factors on surface traffic at the airport. Inputs to TAXSIM include the taxiway structure and routes, runway data, aircraft characteristics, airline data, and aircraft separations. The outputs provide considerable details on the airport activity and congestion, including average utilization and delay by taxiway segment for both arrivals and departures. FTA has applied TAXSIM to airports around the world, including Schiphol (Amsterdam), Munich, and the proposed second Bangkok International airport.
Delays Model (DELAYS):  DELAYS is an analytical queuing theory model originally developed at MIT.  The model treats the airport as a queuing system and uses capacity and demand streams to estimate average, hourly, and peak delays.  This analytical model serves as the underlying delay calculator for FTA's DELAYSIM model.
Gate Assignment Simulation (GATESIM):  GATESIM is a C++ Monte Carlo simulation of the gate assignment process at an airport. Using real or forecast arrival schedules, the model uses stochastic variables to represent the turnaround time of various categories of aircraft. Given assumptions about gate capacities and terminal assignments, the model generates a schedule of gate use for an airport. GATESIM was used at Logan as part of the Beyond Logan 2000 project to model current and future operations and gate requirements. This analysis was used to determine the potential benefits and impacts of changes in airline terminal assignments.
Runway Capacity Model (RUNCAP):  RUNCAP estimates the maximum number of hourly landings and takeoffs that can be conducted for a given runway system. It is an analytical model and is useful for quickly exploring the potential effects on capacity of technical improvements and/or administrative decisions.  Unlike many analytical models, it is capable of handling complex runway configurations, but its simplicity and limited data requirements make it possible to generate answers more quickly than with a simulation tool such as FTA's FLAPS model.
Terminal and Roadway Model (LANDSIDE): LANDSIDE is an analytical model developed to assist airport operators in the quantitative assessment of the adequacy of the airport landside. The primary measures of adequacy are passenger delay and passenger processing time. Detailed analytic models have been implemented for those airport landside components which are essential to passenger processing, and a methodology has been developed to quantify airport landside delay and capacity. This methodology has been applied to existing and planned facilities at several large U.S. hub air carrier airports as well as international airports. 
Terminal Operations Simulation (TOPSIM):  TOPSIM is a simulation model intended for use in landside capacity analysis. The model simulates the movements of originating, terminating and transferring passengers and accompanying visitors between the airport boundary and the aircraft gate. Quantified measures of congestion including queue length, waiting time, and occupancy are produced for variable demand levels at simulated landside processing facilities. Dynamic changes in these quantities may be observed through use of the model when transient effects due to changes in demand or service capacities are simulated. Furthermore, a level of service indicator such as average waiting time at all facilities may be obtained at specific demand levels and used for determining landside capacity.
Ground Noise Propagation Model (GNPM):  GNPM estimates the distribution of ground noise due to aircraft operating on the taxiways or holding in queues near the runways.  Beyond the typical analysis of flight noise, community impacts that may occur as a result of ground operations can now be quantitatively measured and evaluated.  GNPM began with the United States Army’s CERL SoundProp model and was extensively modified by FTA.  GNPM has been used extensively at Boston’s Logan International Airport, and an interface with the Airport Machine has been added to allow Airport Machine taxiway analysis to feed directly into the noise modeling.  The model has also been used to analyze aircraft impacts at Philadelphia International Airport.
Fleet Assignment Model (FLEETASSIGN):  FLEETASSIGN is a planning tool that analyzes a set of data describing an airline or airport network and determines the most profitable combination of routes, aircraft, and frequencies. The model uses mathematical programming techniques to solve a series of linear equations describing the air route network and resources, and it is applicable to scheduled service for passengers and cargo, both international and domestic. FLEETASSIGN serves as a decision support tool to assist both airline and airport management in marketing, fleet planning, and network optimization analyses. While the traditional objective of FLEETASSIGN is to maximize airline profits, other objectives, such as minimization of losses or fuel, can be easily formulated and substituted as model criteria.

Third Party Tools and Models

Total Airspace and Airport Modeller (TAAM): TAAM is a large-scale rules-based fast-time simulation package for modeling entire air traffic systems, developed by te Preston Group (TPG) in cooperation with the Australian Civil Aviation Authority (CAA). It is probably the most capable general purpose simulation for modeling airspace, runway, taxiway and apron operations. It has a high-fidelity graphics display and tremendous flexibility for handling simulation options. In a recent study for Sydney Airport (Australia), FTA and others used TAAM to examine the benefits of a variety of proposed taxiway improvements. 
SIMMOD: This is the most widely used general-purpose airfield/airspace simulation model. Originally sponsored by the FAA, there are versions for DOS, UNIX and Windows 95/98. The FAA has turned development over to the Center of Excellence at MIT under the direction of FTA co-founder Professor Amedeo Odoni.  FTA most recently worked with SIMMOD in Seoul, Korea for Inchon International Airport, developing conceptual arrival and departure procedures for the simulation analysis.  
The Airport Machine: The Airport Machine is another general purpose simulation model with graphical capabilities similar to SIMMOD and TAAM. Developed by Airport Simulation International, the Airport Machine simulates airport operations on a node-link network representing flows from the outer marker to the gate for arrivals and from the gate until immediately after take-off for departures. FTA has developed interfaces between its own proprietary models (FLAPS and DELAYSIM) and the Airport Machine and worked with the model to perform analysis at Boston's Logan International Airport.
Integrated Noise Model (INM): INM is the industry standard for the evaluation of aircraft noise impacts in the vicinity of airports. The FAA has made available a Windows version that, among other improvements, allows nearly seamless integration of radar, population, and OAG data. FTA has extensive experience with the model, most recently at Boston’s Logan International Airport and Philadelphia International Airport. 
Collision Risk Model (CRM): The International Civil Aviation Organization (ICAO) developed CRM for use in determining the risk associated with obstacles located beneath the ILS final approach path. Previously available for use only on a main-frame, FTA has modified this tool for use on desk-top computers. The company has applied the model in several projects including planning of the Inchon International Airport near Seoul, Korea.
Runway Exit Design Interactive Model (REDIM): Developed by the FAA, this model incorporates several specific airfield variables that affect landing performance of aircraft as well as other important operational constraints (e.g., aircraft mix) that have a direct impact on the selection of turnoff location and geometry.  FTA has experience with this model, and often uses it to calibrate the landing simulation portion of the FLAPS model. 


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