Background

Increases in air traffic have resulted in growing delays and denied service at the Colorado mountain airports, especially during bad weather. Instrument meteorological conditions can reduce aircraft acceptance rates for these airports from 12 to 17 flights per hour, to only four per hour. From November to April each year, the Colorado Department of Transportation estimates 75 aircraft per airport, per day, are delayed or diverted, resulting in major revenue loss for the state.

In 2005, the FAA, at the request of the State of Colorado Department of Transportation’s Division of Aeronautics, conducted an analysis of these delays and cancellations. The FAA study determined that the lack of surveillance contributed to reduced capacity during instrument meteorological conditions, and identified multilateration as the preferred solution for providing surveillance to the Colorado mountain airports.

In September 2006, the FAA and the State of Colorado Department of Transportation’s Division of Aeronautics signed a Memorandum of Agreement for a project to plan, install, test, and commission a surveillance system for the Colorado mountain airports. Under this agreement, the state would acquire equipment and equipment sites, including power and telecommunications. The FAA would certify and commission the system, assume ownership following a site acceptance test, provide life-cycle operations and maintenance support, and upgrade with an ADS-B capability to incorporate Universal Access Transceiver (note: Two ADS-B frequencies have been designated for use in the national airspace system — the 1090MHz Extended Squitter for commercial aircraft and 978MHz Universal Access Transceiver for general aviation and airport vehicles). Surveillance data from the system will be sent to the Denver Air Route Traffic Control Center and used to provide surveillance services.

In June 2007, the State of Colorado Department of Transportation's Division of Aeronautics awarded a contract to Sensis Corp. for a multilateration/ADS-B system. The system is designed to alleviate congestion and delays due to weather and the lack of surveillance at these Colorado mountain airports.

Status of the Colorado Project

Wide-Area Multilateration (WAM), began initial operations on September 12, 2009 at Denver Center serving the Yampa Valley-Hayden, Craig-Moffat, Steamboat Springs and Garfield County Regional-Rifle Airports. The WAM capability will provide these airports with improved safety, efficiency and capacity by allowing controllers to see aircraft that are outside radar coverage saving time and money that would otherwise be lost due to flight delays and cancellations or diversions to other airports.