PBN - Performance Based Navigation and RNP - Required Navigation Performance
The need for increased aircraft separation, obstacle clearance and efficiency requirements has led the FAA to define the framework for what is called "Performance Based Navigation". Within the framework of Performance Based Navigation the FAA has designed the RNP "Required Navigation Performance" specification.
As of February 11, 2010, there are currently 1,975 published WAAS LPVs. See the FAA site for further details.
RNP or Required Navigation Performance is a specification designed by the FAA that requires aircraft navigation systems to monitor the performance and accuracy of the navigation system device. Furthermore, RNP provides a means to alert the flight crew of the navigation system's performance.
A "Corridor" or "Virtual Highway in the Sky" is created using RNP. The virtual highways create more pathways for today's congested National Airspace System allowing smoother flow of air traffic and less restrictions for traffic control. The results of these new corridors or highways save time, fuel and money.
Flight Management Systems are used to navigate RNP procedures. The GPS / IRS / INS systems are used by the FMS to calculate the precision "corridor" or "highway" of an RNP procedure. Maintaining a narrow "RNP" corridor of flight space in both vertical and lateral planes allows for increased aircraft operations for any given period of time.
RNP Approaches
RNP Approaches are given a RNP Value. The RNP Value is a lateral width figure. RNP Values are shown as nautical miles such as "RNP 0.3". RNP values will vary with different approaches as required due to the physical characteristics of the approach.
To execute the RNP approach requires an "SAAAR" approval from the FAA. SAAAR is short for "Special Aircraft and Aircrew Authorization Required"
An excellent example of the RNP approach can be seen at Palm Springs International Airport in California (PSP) "RNAV (RNP) RWY 13R". Through the use of GPS, a precision approach can be incorporated into the mountainous terrain that surrounds the airport.
"RNAV (RNP) RWY 13R"
RNP for Operators
Aircraft operators may apply for RNP approval thru the FAA.
RNP authorizations are issued depending on the individual operators operational procedures and aircraft qualifications. Your local FSDO will issue a LOA with appropriate documentation approval.
RNP for Aircraft
Aircraft must qualify for RNP capability by means of qualifying documentation which identifies the optional capabilities of navigation systems installed in type aircraft. The qualifying documentation must also show a means of RNP maintenance procedures.
Honeywell offers an excellent video describing the benefits and uses of RNP