FAA roadmap calls for gradual introduction of Rnav and RNP

 - August 11, 2008, 9:20 AM

The FAA has released a “roadmap” for performance-based navigation that would enable pilots to use Rnav and RNP (required navigation performance) procedures in all phases of flight in the National Airspace System (NAS) by 2020, leaving only a minimal network of ground-based navaids in place.

In the near term (2003 to 2006), the first set of public Rnav and RNP guidelines will be implemented while the FAA continues to work on more widespread operations. The midterm (2007 to 2012) will see Rnav become the primary means of navigation in the NAS and the beginning of the end for ground-bound navigation beginning in 2010. The key to the far term (2013 to 2020) is for operators to continue to modernize their fleets based on previously demonstrated benefits.

“By adopting performance-based navigation standards and leveraging existing and emerging navigation capabilities, we will be able to improve airspace design and air-traffic procedures,” said FAA Administrator Marion Blakey. “This will let us increase access, reduce delays and improve the efficiency of the National Airspace System.”

The FAA and industry will update the roadmap periodically based on the evolution of aircraft capabilities, lessons learned and key decisions. According to the agency, future versions will document more detailed plans for the mid- and far-term implementations while maintaining the overall strategy and vision of the first version released in July.

At the end of the far-term phase in 2020, RNP operations will be available for almost all airspace and operations supporting FAA and industry goals and objectives. Operators will continue to use published routes and tracks for flight planning, and ATM personnel will continue to use them for strategic planning.

A full complement of automation tools that will provide strategic and tactical-conflict detection resolution–based on both published and random routes–will characterize the ATM system. A cooperative system established between the service provider and the operators that will aid in coordinating the traffic flow into major terminal areas will be another facet of the system.

Satellite navigation will be the primary base for the navigation infrastructure, although there will be a network of ground-based navaids to provide continued safe operation in the event of GPS failure.

The FAA acknowledged that a mixed-aircraft-capability environment remains a challenge that the community will need to address in its transition strategy for the far term, but the agency said it is committed to providing benefits to operators capable of performance-based navigation without adversely affecting noncapable operators. “This involves ongoing benefits, tradeoffs and policy considerations,” the FAA admitted.

AOPA said that today’s avionics equipment will continue to serve GA pilots well into the future. VFR aircraft would be exempted from RNP requirements, IFR aircraft could participate using today’s IFR-certified GPS receivers and RNP will provide benefits for GA pilots, even though it is driven by the airlines.

“If you’ve already invested in an IFR-certified GPS, you’re set for RNP operations down to nonprecision approaches,” said Randy Kenagy, AOPA senior director of advanced technology. “For precision approaches, your trusty ILS or new WAAS receiver will do just fine for years to come.”

AOPA said it obtained commitments from the FAA to quickly establish transition routes through Class B airspace and reduced minimum altitudes on existing airways where current ground-based navaids push them excessively high. Additionally, the FAA agreed to change the method by which minimums are established for both precision and nonprecision GPS approaches, which AOPA said will mean more approaches to lower minimums.

The aviation industry and the FAA worked together to develop the roadmap, which defines performance-based navigation as navigation along a route, in a procedure or airspace within which the aircraft operating must comply with specified performance requirements. Joint government/industry groups such as the Terminal Area Operations Aviation Rulemaking Committee and the RTCA Free Flight Steering Committee provided recommendations.

The FAA said the roadmap is consistent with the RTCA’s NAS concept of operations and the FAA strategic plan and operational evolution plan, and takes into account the results of additional FAA programs to speed benefits to operators and service providers.

Performance-based navigation will:

• Increase safety through continuous descent procedures that reduce the risk of controlled flight into terrain and loss of control. Predefined Rnav and RNP procedures enhance confidence and consistency and reduce the risk of communication errors.

• Improve airport and airspace access in all weather conditions and the ability to meet environmental and obstacle-clearance constraints through the application of optimized Rnav-based flight tracks. The result will be reduced lateral separation criteria and more accurate path keeping.

• Enhance reliability, repeatability and predictability of operations, leading to increased throughput. More precise arrival, approach and departure procedure will reduce dispersion and facilitate smoother traffic flows.

• Increase schedule reliability through more consistent access and throughput in all weather conditions.

• Reduce delays at airports and in certain dense airspace through the application of new parallel routes; newly enabled ingress/egress points around busy terminal areas; improved flight-rerouting capabilities, making better use of closely spaced procedures and airspace; and deconflicting adjacent airport flows.

• Increase efficiency through less circuitous routes and optimized airspace, especially in lower flight altitudes.

• Enable flexible routes such as wind-optimal and great circle routes when beneficial.

• Promote design and use of environmentally beneficial arrival and departure procedures that allow the aircraft systems to manage flight performance (climb, descent, engine performance and so on). Benefits include reduced fuel emissions and environmentally tailored noise footprints.