A required navigation performance (RNP) authorization required (AR) approach is a particular type of approach to landing developed according to the performance-based navigation (PBN) concept. An RNP AR approach requires a higher level of performance, and it allows for a reduced protected area for obstacle clearance. In addition to implying specific qualification levels for the aircraft, the airport and the flight crew, RNP AR approaches often also require a flight operational safety assessment (FOSA) — a review of the aircraft, crew and operating environment to ensure all-around safety.
