A Technology Partnership for the New Millennium

Future Flight Image in a Diamond Shape

5.5 Safe Flight 21

The Safe Flight 21 program is a joint government/industry initiative designed to demonstrate and validate, in a real-world environment, the capabilities of advanced communication, navigation, and surveillance, and air traffic procedures associated with free flight. The program will demonstrate the following free flight operational enhancements selected by RTCA, using automatic dependent surveillance-broadcast (ADS-B) as an enabling technology:

  • Weather and other information in the cockpit.
  • Affordable means to reduce controlled flight into terrain (cfit)
  • Improved capability for approaches in low visibility conditions
  • Enhanced capability to see and avoid adjacent traffic
  • Enhanced capability to delegate aircraft separation authority to the pilot
  • Improved capability for pilots to navigate airport taxiways
  • Enhanced capability for controllers to manage aircraft and vehicular traffic on the airport surface
  • Surveillance coverage in nonradar airspace
  • Improved separation standards

The Safe Flight 21 program will also take the following into account over the course of demonstrating these nine operational enhancements: safety, efficiency, capacity, certification, pilot/controller situation awareness, human factors, spectrum, and affordability issues.

Two gentlemen looking at computer terminals

The potential market for ADS-B implementation is huge. If ADS-B, FIS-B, and TIS-B are included in the NAS Architecture, over 10,000 aircraft and thousands of ground stations may need to be equipped. The international marketplace is just as large. Success of the Safe Flight 21 demonstrations are critical to opening these markets up. As an enabling technology, ADS-B will provide the means for airborne aircraft to broadcast their position to other aircraft and to ground stations. ADS-B avionics will periodically transmit aircraft location, altitude, velocity, and other data derived from either GPS or flight instruments via a digital link. Onboard aircraft, ADS-B information will be displayed on a multifunction display, such as a Cockpit Display of Traffic Information (CDTI). The intent of broadcasting this information is to increase the pilots' situational awareness of ADS-B equipped aircraft. ADS-B can also be used to provide air traffic controllers with a consolidated picture of the controlled airspace. The information provided to controllers will be more frequently updated than that provided by other surveillance equipment. In addition, ADS-B can be used as the enabling technology for Flight Information Services-Broadcast (FIS-B) and Traffic Information Services-Broadcast (TIS-B), which will allow weather and other data available on the ground to be provided to the cockpit. As a result, ADS-B capabilities have the potential to significantly increase flight safety, system capacity, and overall efficiency of flight operations.

A van dragging an airplane

The Safe Flight 21 program is based on the principle that government and industry will share in the development of a global air transportation system, as we move into the free flight era.

The FAA is collaborating with industry via RTCA to ensure that the scope, resources, schedule, and execution of the Safe Flight 21 program reflects government/industry consensus. The vehicle for this collaboration is the RTCA Safe Flight 21 Steering Committee, which includes representatives from the Aircraft Operators and Pilots Association (AOPA), Air Line Pilots Association (ALPA), National Air Traffic Control Association (NATCA), Cargo Airline Association (CAA), U.S. Airways, United Airlines, Delta Airlines, and the FAA.

The FAA and the CAA are entering into a partnership to pool their resources, in a collaborative effort to conduct an operational evaluation of ADS-B capabilities in the Ohio Valley. The CAA began equipping its aircraft in late 1998 as a prelude to in-flight evaluations, focusing on the air-air use of the equipment for "see and avoid" applications. A subsequent operational evaluation, during Summer 1999, employed both avionics and ground stations to demonstrate expected operational enhancements from ADS-B, including the broadcast of TIS and FIS information, and at the same time gathered critical data on the three candidate ADS-B links (Mode Select (Mode S) Extended Squitter, Universal Access Transceiver (UAT), and VHF Data Link (VDL)( Mode 4)), and operational procedures.

Through the "Capstone" initiative, the FAA is working with air carriers in the area of Bethel, Alaska, to improve aviation safety while offering greater efficiencies to operators. "Capstone" will concentrate on the evaluation and implementation of three operational enhancements in the region: Weather and Other Information in the Cockpit, Affordable Means to Reduce CFIT, and Enhanced Capability to See and Avoid Adjacent Traffic. An initial operational evaluation occurred during summer 1999, with limited equipage and subsequent operational evaluations following in 2000.

Safe Flight 21 Operational Evaluation

Safe Flight 21 Operational Evaluation

The FAA is working with United Airlines to evaluate Paired Approach and Runway Incursion Protection ADS-B applications at San Francisco. Simulation studies have been performed, and an operations concept is being developed; Further operational evaluations of these applications are currently in the planning stages. The FAA has started soliciting inputs from major potential avionics providers on how to make ADS-B equipment affordable enough to promote widespread voluntary equipage.

Richard Lay


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