What is the required navigation performance for RNP1?

The required navigation performance for RNP1 specifies that an aircraft must maintain a lateral and longitudinal navigation accuracy of ±1 nautical mile (NM) for 95% of the flight time. This requirement ensures a high level of precision in navigation, which is crucial for safety and efficiency, especially in terminal airspace and during approaches.

In practical terms, this means that the aircraft's navigation system must be capable of accurately determining its position within 1 NM for the majority of the flight. This level of performance supports the increasingly complex air traffic management systems and allows for closer spacing of aircraft, which can enhance the capacity of airspace.

Understanding this requirement helps to appreciate why a navigation performance standard is critical, especially in environments where precise navigation is necessary to avoid conflict with other aircraft and to facilitate safe approaches and departures at busy airports. The other options specify varying parameters for lateral and longitudinal navigation performance that do not align with the established standard for RNP1.