Definition
An ICAO-defined set of aircraft and aircrew requirements needed to support performance-based navigation (PBN) operations within a defined airspace. Navigation specifications are of two kinds: an RNP specification, which includes a requirement for on-board performance monitoring and alerting; and an RNAV specification, which does not. Each specification is identified by the navigation accuracy required (for example, RNP 4 or RNAV 1), expressed in nautical miles.
Plain English
A published rulebook that says what an aircraft and its crew must be able to do to fly a given type of route or procedure using satellite or area navigation. It also states how accurate the navigation has to be.
Context Anchor
You may see this term in performance-based navigation material, route or procedure requirements, aircraft approval documents, and international flight planning guidance.
Derivation
From Latin 'navigare' (to sail or steer a ship) and 'specificare' (to state in detail). The term literally means a detailed statement of what is required to navigate. In ICAO usage it became the formal name for the rules that pin down navigation performance.
Why Pilots Care
It determines whether an aircraft is eligible to use efficient routes with reduced separation in designated airspace.
Intuition Check
Do not read “specification” as just an equipment list. Here it means the full operating standard: aircraft capability, accuracy, crew training, and procedures.
Example Sentence 1
Before filing the oceanic route, the crew confirmed the aircraft was approved for the RNP 4 navigation specification.
Example Sentence 2
Before departure the dispatcher verified the navigation specification matched the planned airspace.