22.1 General
22.1.1 Area Navigation (RNAV) provides enhanced navigational capability to the pilot. RNAV equipment can compute the airplane position, actual track and ground speed and then provide meaningful informa-tion relative to a route of flight selected by the pilot. Typical equipment will provide the pilot with distance, time, bearing and crosstrack error relative to the selected “TO” or “active” waypoint and the selected route. Several navigational systems with different navigational performance characteristics are capable of providing area navigational functions. Present day RNAV includes INS, LORAN, VOR/ DME, and GPS systems. Modern multi.sensor systems can integrate one or more of the above systems to provide a more accurate and reliable navigational system. Due to the different levels of performance, area navigational capabilities can satisfy different levels of required navigation performance (RNP).
22.2 RNAV Operations Incorporating RNP
22.2.1 During the past four decades, domestic and international air navigation have been conducted using a system of airways and instrument procedures based upon ground.based navigational systems such as NDB, VOR, and ILS. Reliance on ground.based navigational systems has served the aviation community well, but often results in less than optimal routes or instrument procedures and an inefficient use of airspace. With the widespread deployment of RNAV systems and the advent of GPS.based navigation, greater flexibility in defining routes, procedures, and  airspace design is now possible with an associated increase in flight safety. To capitalize on the potential of RNAV systems, both the FAA and International Civil Aviation Organization (ICAO) are affecting a shift toward a new standard of navigation and airspace management called RNP.
22.2.2 Navigational systems are typically described as being sensor specific, such as a VOR or ILS system. By specifying airspace requirements as RNP, various navigation systems or combination of systems may be used as long as the aircraft can achieve the RNP. RNP is intended to provide a single

Federal Aviation Administration Twentieth Edition
performance standard that can be used and applied by aircraft and aircraft equipment manufacturers, airspace planners, aircraft certification and opera-tions, pilots and controllers, and international aviation authorities. RNP can be applied to obstacle clearance or aircraft separation requirements to ensure a consistent application level.
22.2.3 ICAO has defined RNP values for the four typical navigation phases of flight: oceanic, en route, terminal, and approach. The RNP applicable to a selected airspace, route, or procedure is designated by it’s RNP Level or Type. As defined in the Pilot/Controller Glossary, the RNP Level or Type is a value typically expressed as a distance, in nautical miles, from the procedure, route or path within which an aircraft would typically operate. RNP applications also provide performance to protect against larger errors at some multiple of RNP level (e.g., twice the RNP level).
22.3 Standard RNP Levels
22.3.1 U.S. standard values supporting typical RNP airspace are as specified in TBL ENR 4.1.6 below. Other RNP levels as identified by ICAO, other states and the FAA may also be used.
TBL ENR 4.1.6
U.S. Standard RNP Levels
RNP Level  Typical Application 
.3  Approach 
1  Departure, Terminal 
2  En Route 

22.3.1.1 Application of Standard RNP Levels.
U.S. standard levels of RNP typically used for various routes and procedures supporting RNAV operations may be based on use of a specific navigational system or sensor such as GPS, or on multi.sensor RNAV systems having suitable perfor-mance. New RNAV routes and procedures will be FAA’s first public use procedures to include a specified RNP level. These procedures are being developed based on earth referenced navigation and do not rely on conventional ground.based naviga-tional aids. Unless otherwise noted on affected charts or procedures, depiction of a specified RNP level will not preclude the use of other airborne RNAV navigational systems.
22.3.1.2 Depiction of Standard RNP Levels. The applicable RNP level will be depicted on affected charts and procedures. For example, an RNAV departure procedure may contain a notation referring to eligible aircraft by equipment suffix and a phrase “or RNP.1.0.” A typical RNAV approach procedure may include a notation referring to eligible aircraft by specific navigation sensor(s), equipment suffix, and a phrase “or RNP.0.3.” Specific guidelines for the depiction of RNP levels will be provided through chart bulletins and accompany affected charting changes.
22.4 Aircraft and Airborne Equipment Eligibil-ity for RNP Operations. Aircraft meeting RNP criteria will have an appropriate entry including special conditions and limitations, if any, in its Aircraft/Rotorcraft Flight Manual (AFM), or supple-ment. RNAV installations with AFM.RNP certifica-tion based on GPS or systems integrating GPS are considered to meet U.S. standard RNP levels for all phases of flight. Aircraft with AFM.RNP certifica-tion without GPS may be limited to certain RNP levels, or phases of flight. For example, RNP based on DME/DME without other augmentation may not be appropriate for phases of flight outside the certified DME service volume. Operators of aircraft not having specific AFM.RNP certification may be issued operational approval including special condi-tions and limitations, if any, for specific RNP levels. Aircraft navigation systems eligible for RNP airspace will be indicated on charts, or announced through other FAA media such as NOTAMs and chart bulletins.
　
中國航空網 m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：美國航行情報匯編 AERONAUTICAL INFORMATION PUBLICATION AIP 3(47)