The issue of airport noise is at the forefront of ongoing efforts to develop the United States airport system infrastructure. United States lawmakers, such as Senator Kay Bailey Hutchison (R-Texas), are looking for ways to streamline the environmental/noise review process that airports must endure before needed runways, taxiways, and terminals can be developed. Airport noise is an area of focus and debate in local and national political circles and remains one of the greatest impediments to airport development.

In Minnesota, at the Minneapolis-St. Paul International Airport (MSP), this issue is at the heart of coordinated efforts with the airlines and communities surrounding the airport. Since the late 1960s, extensive noise mitigation efforts at MSP have been developed and enhanced in an effort to reduce noise impacts on surrounding communities. When translated into dollars, this effort equates to substantial expenditures, the most prevalent being the residential home noise insulation program. When complete, this program, in addition to other land use efforts, will have provided mitigation costing approximately $400 million to more than 7,800 homes.

One way to develop public trust relative to airport noise is good communication of factual and meaningful information. GIS has played a critical role in these efforts including various airspace use and noise impact evaluations, home noise insulation program management, and, more recently, Internet mapping applications.

The most effective way to avoid exacerbation of the issue is to proactively inform and educate affected residents, prospective homebuyers, and real estate agents. The information dissemination flexibility that the Internet provides, coupled with interactive mapping capabilities, allows the public to gain new levels of insight relative to the multiple operational modes of the airport and their resulting noise impacts.

Specifically, the issue of cultivating public trust can be fostered when information is provided in a way that is objective and factual. The efforts taken at MSP to provide interactive access to actual flight track and noise data via the Internet is a testament to such initiatives. Providing applications with which users can generate their own reports and conduct their own analyses diminishes any grounds for accusations of bias reporting and hidden agendas on behalf of the airport operator.

The Metropolitan Airports Commission (MAC) Aviation Noise and Satellite Programs Office, in a partnership with DiscoverCast, Inc., of San Diego, California, has developed interactive flight track and noise information mapping applications on the MAC Aviation Noise and Satellite Programs Web site (www.macavsat.org). Through the integrated use of DiscoverCast software, Esri's ArcSDE 8.02 and ArcIMS 3.1, and Oracle 8i, the overflight track mapping applications offer the ability to view and replay flight tracks and measured noise events relative to a submitted address, a default airport view, or to whatever view extent the user selects. Custom controls allow the user to navigate around the map while replaying airspace usage at actual or fast-forward speeds. In addition, the aircraft operation replay capability provides the location of 39 permanent noise-monitoring towers located around the airport and graphically depicts the aircraft noise event fluctuations at those locations.

In addition to starting and viewing their own map session, users can join other active sessions and communicate textually in real time while viewing the exact same map and data. The ability of users to join other sessions and communicate is possible through the collaborative functionality offered by the DiscoverCast software.

The data utilized by these flight track mapping applications is extracted from the Metropolitan Airports Commission's Airport Noise and Operations Monitoring System (ANOMS). This UNIX-based computer system provides aircraft location data (flight tracks) from the Federal Aviation Administration's (FAA) radar located on the airport.

By importing this information into Oracle database tables, the operation and noise data is accessed and displayed on a map via ArcSDE, ArcIMS, and DiscoverCast software. By clicking on a specific flight track, users can determine the type of aircraft, whether the operation was an arrival at or departure from the airport, the runway that was used, and the nature of the operation (i.e., carrier jet, prop aircraft, corporate jet, etc.).

In addition to the aircraft/operation specific information, the user is provided specific details of noise events at any one of the permanent noise monitoring towers, including start time, location, and decibel level.

The mapping applications available on the MAC Aviation Noise and Satellite Programs Web site are an important part of the success of the noise programs at MSP. The ability for users to generate their own customized reports and/or analyses allows MAC staff to focus activities on other noise reduction tasks. Traditionally, staff time would have been dedicated to providing the mapping information that is now interactively available on the Web site to those who request it.

It is no surprise that efforts that can reduce or prevent the introduction of incompatible residential land uses around an airport are extremely desirable to both airports and airlines alike.

For more information, contact Chad Leqve, manager, Aviation Noise and Satellite Programs (tel.: 612-725-6326, fax: 612-725-6310, e-mail: cleqve@macavsat.org) or Mark Kill, GIS specialist (tel.: 612-725-6156, fax: 612-725-6310, e-mail: mkill@macavsat.org), Metropolitan Airports Commission, 6040 28th Avenue South, Minneapolis, Minnesota 55450 or visit www.macavsat.org.