Definition
A navigation specification based on area navigation that prescribes the performance requirements, equipment standards, and operational rules for aircraft and crew operating in a defined airspace or on a defined route, but which does not require onboard performance monitoring and alerting. RNAV specifications are designated by the prefix RNAV (for example, RNAV 1, RNAV 2, RNAV 5), where the number indicates the lateral navigation accuracy in nautical miles that must be maintained for at least 95 percent of the flight time.
Plain English
A set of rules that says what kind of navigation gear an aircraft must have, how accurate it has to be, and how the crew must use it when flying a particular route or in a particular airspace. The aircraft does not have to alert the crew on its own if accuracy is lost.
Context Anchor
Seen when checking whether an aircraft is approved for an RNAV route, departure, arrival, or approach procedure.
Derivation
RNAV stands for area navigation, meaning navigation that allows flight on any desired path within the coverage of ground- or space-based navaids, rather than only directly to or from a station. 'Specification' here means a formal published standard, not a casual description.
Why Pilots Care
Determines which RNAV routes, departures, and approaches an aircraft is legally allowed to fly based on its equipment approval.
Intuition Check
Do not read “specification” as just a description on a chart. Here it means a requirement your aircraft and crew must meet before using that RNAV operation.
Example Sentence 1
The departure procedure required compliance with the RNAV 1 specification, so the crew confirmed their navigation system met the accuracy and equipment requirements before takeoff.
Example Sentence 2
Flight planning software flags any RNAV specification the aircraft is not equipped to satisfy.