Figure 2-55. Computer navigation fix.  Required Navigation Performance  2-34  Figure 2-56. U.S. standard RNP levels.  The RNP capability of an aircraft varies depending upon  the aircraft equipment and the navigation infrastructure.  For example, an aircraft may be equipped and certified  for RNP 1.0, but may not be capable of RNP 1.0 operations  due to limited NAVAID coverage.  Required navigation performance (RNP) is RNAV with  onboard navigation monitoring and alerting. RNP is also  a statement of navigation performance necessary for  operation within a defined airspace. A critical component  of RNP is the ability of the aircraft navigation system to  monitor its achieved navigation performance, and to  identify for the pilot whether the operational requirement  is, or is not being met during an operation. This onboard  performance monitoring and alerting capability;  therefore, allows a lessened reliance on ATC intervention  (via radar monitoring, automatic dependent surveillance- broadcast (ADS-B), multilateration, communications),  and/or route separation to achieve the overall safety of  the operation. RNP capability of the aircraft is a major  component in determining the separation criteria to  ensure that the overall containment of the operation is  met.  Many of the RNAV systems available today make it all  too easy to forget that en route charts are still required  and necessary for flight. As important as databases are,  they really are onboard the aircraft to provide navigation  guidance and situational awareness (SA); they are not  intended as a substitute for paper charts. When flying  with GPS, FMS, or planning a flight with a computer, it is  critical to understand the limitations of the system you are  using, for example, incomplete information, unloadable  procedures, complex procedures, and database storage  limitations.  NOT FOR NAVIGATION 0.1 to 1.0  0.3 to 1.0  1  2  RNP AR Approach Segments  RNP Approach Segments  Terminal and En Route  En Route  0.1 to 1.0  0.3 to 1.0  1.0  2.0  RNP Level  Typical Application  Primary Route Width (NM) - Centerline to Boundary 