July 29, 2009
Before the House Committee on Transportation and Infrastructure, Subcommittee on Aviation on Nextgen: Area Navigation (RNAV)/Required Navigation Performance (RNP)
Chairman Costello, Congressman Petri, and Members of the Subcommittee:
Thank you for inviting me here today to discuss the Federal Aviation Administration's program for area navigation (RNAV) and required navigation performance (RNP) air traffic control routes. RNAV/RNP is a building block for the Next Generation Air Transportation System (NextGen), and has already shown great promise in enhancing safety and efficiency in the National Airspace System (NAS).
Through NextGen, the FAA is addressing the impact of air traffic growth by increasing NAS capacity and efficiency while simultaneously improving safety, reducing environmental impacts, and increasing user access to the NAS. To achieve its NextGen goals, the FAA is implementing new Performance-Based Navigation (PBN) routes and procedures that leverage emerging technologies and aircraft navigation capabilities.
PBN is a framework for defining performance requirements in "navigation specifications," that is, to specify that the avionics can function in a particular way or ways, that the pilot is appropriately trained and follows certain procedures in the cockpit. PBN can be applied to an air traffic route, instrument procedure, or defined airspace. PBN provides a basis for the design and implementation of automated flight paths as well as for airspace design and obstacle clearance. Once the required performance level is established, the aircraft's own capability determines whether it can safely achieve the specified performance and qualify for the operation.
Prior to satellite navigation capabilities, i.e. global positioning systems or GPS, aircraft could only navigate primarily by ground-based navigation aids, such as VHF Omni-directional Range (VOR) equipment. This limited the routes that aircraft could take, depending on the location and position of those ground-based aids, and necessarily involved certain inefficiencies during flight, e.g., instead of flying a direct route, an aircraft might have to take a more circuitous route in order to navigate from ground-based point to ground-based point.
Now, with advances in technology, we are able to take advantage of space-based navigation sources that provide for additional navigational coverage. An aircraft using RNAV can fly on any desired flight path within the coverage of ground- or space-based navigational aids, within the limits of the capability of the systems onboard the aircraft, or a combination of both capabilities. As such, RNAV aircraft have better access and flexibility for point-to-point operations. This leads to the potential for flights to reduce the miles flown, save fuel, and enhance efficiency.
RNAV also helps solve operational issues. For example, an RNAV approach may be available in areas where we cannot install or maintain a ground-based navigational aid, such as in Alaska, where the terrain either does not permit the ability to install the navigational aid or the weather conditions preclude us from being able to maintain the operability of the navigational aid.
RNP is RNAV with the addition of an onboard performance monitoring and alerting capability. A defining characteristic of RNP operations is the ability of the aircraft navigation system to monitor the navigation performance it achieves and inform the crew if the requirement is not met during a flight operation. This onboard monitoring and alerting capability enhances the pilot's situational awareness and can enable reduced obstacle clearance or closer route conformance without intervention by air traffic control.
Certain RNP operations require advanced features of the onboard navigation function and approved training and crew procedures. These operations must receive approvals known as Special Aircraft and Aircrew Authorization Required (SAAAR), similar to approvals required for operations to conduct Instrument Landing System Category II and III approaches. In addition to certified avionics, the flight crew must be trained and authorized to fly these complex procedures.
The attached chart shows how RNAV and RNP have improved the navigational process. See Figure 1 below. As you can see, using the current ground navaids, the aircraft has to fly from beacon to beacon, often taking an inefficient route in order to pick up the signals at the appropriate place in the air. The dotted boxes indicate the expanse of the area in the sky that the aircraft could be in as it picks up those ground-based signals. This requires our air traffic control to create larger areas of separation between aircraft, in order to maintain safety. In the RNAV and RNP routing, however, the dotted areas are far smaller, indicating that the aircraft can fly a much more precise route in the air. Additionally, the graphic illustrates the RNP "radius to turn" ability, essentially indicating how RNP enables the aircraft to make much tighter, more precise turns in the air. This is particularly useful in areas where the airspace is congested and there are multiple busy airports. The ability of the aircraft to use these "radius to turn" procedures means air traffic is easier to "deconflict," or route in a manner that avoids other air traffic paths.

Figure 1. Performance-Based Navigation: RNAV/RNP
RNAV and RNP capabilities facilitate more efficient design of airspace and procedures which collectively result in improved safety, access, capacity, predictability, and operational efficiency, as well as reduced environmental impacts. Specifically, improved access and flexibility for point-to-point operations help enhance reliability and reduce delays by defining more precise terminal area procedures. They also can reduce emissions and fuel consumption.
RNAV procedures can provide benefits in all phases of flight, including departure, en route, arrival, approach, and transitional airspace. For example, Standard Terminal Arrivals (STARs) can:
RNAV/RNP procedures have been developed by the FAA, with the support of industry and MITRE, in a complex, multi-layered process. For Terminal RNAV procedures (those RNAV procedures in the airspace into an airport terminal environment), for example, there is an 18-step implementation process. See Figure 2 below.

Figure 2. 18-Step Guidelines for Terminal RNAV Procedure Implementation
Several offices within the FAA play essential roles in the development of these procedures. Their various duties are outlined below:
RNAV/RNP Group
Aviation System Standards
Field Facilities
Flight Standards Service
Aircraft Certification
Air Traffic Safety Oversight Service
Currently, we have 159 RNAV routes and 270 RNAV arrival and departure procedures implemented into the NAS and 163 RNP SAAAR approach procedures. By the end of fiscal year 2009, we anticipate that we will have an additional 48 RNAV routes, 35 RNAV arrival and departure procedures, and 29 RNP SAAAR approach procedures in place. Additionally, other PBN procedures such as Localizer Performance with Vertical Guidance approaches throughout the NAS elevate the overall number of Performance Based Procedures to over 8,000.
The development of RNAV/RNP procedures is a relatively young program at the FAA. The agency only began developing these procedures in 2002. Along the way, we have encountered some challenges and learned from them. We intend to apply those lessons moving forward.
While we have a standard process for developing RNAV/RNP procedures in the Terminal area, we did not have a comparable process for developing procedures elsewhere in the operational environment. We believe this as an area in which we could improve, and have asked for an agency-wide mapping of all PBN processes to standardize how we develop, test, chart, and implement Performance-Based Navigation procedures. I am pleased to report that we should be starting work on that Process Mapping in the next couple of weeks.
As we move forward, there are other challenges that continue to face us in the advancement of RNAV/RNP. For example:
Some of our other technical challenges are illustrated in the graphic below. See Figure 3.

Figure 3. RNAV/RNP Implementation and Challenges
As you can see, the FAA has developed a solid foundation of routes and procedures for RNAV/RNP, which serves as a platform of the enhanced safety and efficiency goals of NextGen. Since we have this foundation, we are transitioning from a site-by-site (or runway-by-runway) implementation process toward a NextGen readiness concept that would include development of an integrated system of PBN routes and procedures NAS-wide. This broader view will go further in advancing NextGen and better accommodate our intent to accelerate NextGen as much as possible. In the end this integrated approach will optimize benefits for operators, and ultimately, the traveling public. While we anticipate challenges along the way, we have learned from our work over the past few years and are prepared to meet those challenges effectively.
Mr. Chairman, Ranking Member Petri, Members of the Subcommittee, this concludes my prepared remarks. I would happy to answer any questions you may have.