RNP 5 (Required Navigation Performance) requires a navigation accuracy of?

RNP 5 (Required Navigation Performance) specifies that an aircraft must maintain a navigation accuracy of plus or minus 5 nautical miles laterally for 95% of the flight time. This standard is crucial for ensuring that aircraft can safely navigate within designated airspace, particularly in areas where precise navigation is necessary for air traffic management and safety.

The requirement for 95% of the flight time indicates that for the majority of the flight, the navigation system must be reliable enough to keep the aircraft within this lateral distance from the intended flight path. This level of accuracy helps to maintain safe separation between aircraft and contributes to the efficiency of air traffic operations by enabling more precise routing and reduced lateral deviations.

The other options provided either specify different degrees of accuracy or different percentages that do not align with the standard set for RNP 5, highlighting why they are not the correct answer. For example, a lateral accuracy of 0.5 NM or a requirement that is based on a 90% measurement does not meet the established criteria for RNP 5.