NextGen and Performance-Based Navigation
The Next Generation Air Transportation System (NextGen) is the FAA’s plan to modernize the National Airspace System (NAS). Through NextGen, FAA is addressing the impact of air traffic growth by increasing capacity and efficiency while simultaneously improving safety, reducing environmental impacts, and increasing user access to the NAS. To achieve its NextGen goals, FAA is implementing new Performance-Based Navigation (PBN) routes and procedures that leverage emerging technologies and aircraft navigation capabilities.
What is Performance-Based Navigation?
Performance-Based Navigation (PBN) is comprised of Area Navigation (RNAV) and Required Navigation Performance (RNP) and describes an aircraft’s capability to navigate using performance standards.
What Is RNAV?
RNAV enables aircraft to fly on any desired flight path within the coverage of ground- or space – based navigation aids, within the limits of the capability of aircraft self-contained systems, or a combination of both capabilities.
What Is RNP?
RNP is RNAV with the addition of an onboard performance monitoring and alerting capability. RNP enables the aircraft navigation system to monitor the navigation performance it achieves and inform the crew if the requirement is not met during an operation. This onboard monitoring and alerting capability enhances the pilot’s situational awareness and can enable reduced obstacle clearance.
Certain RNP operations require advanced features of the onboard navigation function and approved training and crew procedures. These operations must receive approvals that are characterized as Authorization Required (AR), similar to approvals required for operations to conduct Instrument Landing System Category II and III approaches.
RNAV and RNP provide for more efficient design of airspace and procedures which collectively result in improved safety, capacity, predictability, operational efficiency, and environmental impacts. Specifically, improved access and flexibility help to enhance reliability and reduce delays by defining more precise terminal area procedures.
RNAV and RNP provide environmental benefits because aircraft are able to reduce emissions and fuel consumption. RNAV procedures can provide benefits in all phases of flight, including departure, en route, arrival, approach, and transitioning airspace.
Performance-based navigation will:
- Increase safety through continuous descent procedures that reduce the risk of controlled flight into terrain and loss of control.
- Improve airport and airspace access 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 re-routing capabilities, and making better use of closely spaced procedures and airspace; and de-conflicting adjacent to airport flows.
- Increase efficiency through less circuitous routes and optimized airspace, especially in lower flight altitude stratums.
There are four types of PBN procedures: RNAV Standard Instrument Departure (SID), RNAV Standard Terminal Arrival (STAR), Required Navigation Performance (RNP) approach procedures, and RNAV Routes. These procedures reduce the risk of communication errors for pilots and controllers and take advantage of the aircraft’s onboard navigation system.
Other PBN categories include LNAV/VNAV and Wide Area Augmentation System (WAAS) Localizer Performance with Vertical Guidance (LPV) approach procedures. LPV approach procedures are beneficial for smaller airports because it enables general aviation aircraft to land in lower visibility conditions, providing more access to those airports throughout the year.
Optimized Profile Descent is a more efficient method by which aircraft approach airports prior to landing. It is designed to reduce level off during descent thus reducing fuel consumption and noise.
Process improvement Initiatives
An implementation plan called NAV Lean was created to improve and streamline processes used for developing and implementing all instrument flight procedures (IFP) including PBN. The NAV Lean program will produce safe and efficient procedures to help accelerate environmental benefits and save money for the industry.
The FAA is collaborating with the International Civil Aviation Organization (ICAO) and European Organization for the Safety of Air Navigation (EUROCONTROL) to promote global awareness and understanding of PBN. Presently, FAA is involved in a joint ICAO/International Air Transport Association PBN initiative to coordinate/leverage government and industry resources to accelerate PBN implementation internationally. These efforts are helping FAA and ICAO to create the best implementation practices and operational standards.