Definition
An air traffic control procedure that allows controllers to apply reduced separation between aircraft when one or more of them is established on a Required Navigation Performance (RNP) approach with Authorization Required (AR) procedures. Once an aircraft is confirmed established on the published RNP AR approach path, controllers may clear another aircraft for an approach to a parallel or converging runway without applying standard radar separation, because the RNP-equipped aircraft is known to remain within a precisely defined containment area along its curved or offset flight path.
Plain English
A rule that lets controllers run approaches closer together when an aircraft is flying a high-precision RNP approach. Because the aircraft's path is known to stay within very tight limits, the controller doesn't need as much spacing between it and other arriving traffic.
Context Anchor
Seen in procedures for simultaneous instrument approaches, especially where aircraft are flying precise RNP approach paths near other approach traffic.
Derivation
"Established" comes from the Latin stabilire, meaning to make firm or fixed. In ATC usage it means an aircraft is confirmed to be flying the published path with its required navigation performance active. "On RNP" identifies which type of path the aircraft is established on.
Why Pilots Care
It supports more direct routing and efficient traffic flow by reducing the need for extended vectoring before final approach.
Grounding Statement
EoR is the moment or condition where ATC can rely on the aircraft being on its protected RNP approach path.
Intuition Check
Established does not mean the aircraft is merely pointed toward the airport. Here, it means the aircraft is on the approved RNP path closely enough for ATC to use the specific separation rules for that operation.
Example Sentence 1
The controller cleared the second aircraft for the parallel approach using the EoR concept once the first aircraft was confirmed established on the RNP AR approach.
Example Sentence 2
Under the EoR concept, ATC applied reduced separation once the aircraft confirmed it was within tolerances on the RNP approach.