|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
- 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
- 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:
|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
|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
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
|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
|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):
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 Armys CERL SoundProp model and
was extensively modified by FTA.
GNPM has been used extensively at Bostons 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
|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
|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 Bostons 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.