Background

The United States (US) Federal Aviation Administration (FAA) and the International Civil Aviation Organization (ICAO) are transitioning to performance based navigation (PBN). Area navigation (RNAV) procedures are fundamental to this effort. RNAV procedures allow an aircraft to fly directly between points in space without relying on ground-based navigation aids (e.g., by using satellite based navigation). Required navigation performance (RNP) is a refinement of RNAV that includes on-board monitoring and alerting to ensure that the actual performance of the navigation system keeps the aircraft within design requirements. RNP allows even more precise path design, which is particularly useful for developing approach procedures to runways.

Instrument procedures based on RNAV and RNP offer significant safety enhancements along with new levels of flexibility to negotiate terrain, airspace, and environmental considerations. More RNAV procedures, both with and without RNP segments, are being developed each year in order to support PBN (see the FAA's PBN dashboard at www.faa.gov/nextgen/pbn/dashboard/).

Motivation

It is important to address the human factors issues associated with the design, depiction, and implementation of these new procedures because flight path conformance is essential for realizing the benefit of increased efficiency from more precise navigation and reduced flight path spacing that these procedures allow. If human factors considerations are not addressed, there is a greater risk of pilot deviations due to misinterpretation of flight path requirements. There may also be greater potential for programming errors of the flight-path management system, which is used to negotiate and fly precise speed, altitude, and lateral path constraints for RNAV and RNP procedures.

For additional information on RNAV, RNP, and aeronautical charting, see Related Sites.