Definition
A performance-based navigation specification that requires the aircraft's RNAV system to maintain a total system error of no more than 1 nautical mile from the centerline of the intended track for at least 95 percent of the total flight time. RNAV 1 applies to standard instrument departures (SIDs), standard terminal arrivals (STARs), and instrument approach procedures up to the final approach fix.
Plain English
A navigation rule that says the aircraft must stay within 1 nautical mile of its planned path for at least 95 percent of the flight, using its onboard navigation equipment.
Context Anchor
Seen on RNAV departure and arrival procedures, especially when checking whether the aircraft and crew are allowed to fly that procedure.
Derivation
RNAV stands for Area Navigation, meaning the aircraft can fly any path within an area rather than only point-to-point between ground-based stations. The '1' is the accuracy figure in nautical miles. So RNAV 1 simply means area navigation flown to a 1-nautical-mile standard.
Why Pilots Care
It allows precise routing on departures without ground-based navigation aids, improving efficiency and flexibility.
Grounding Statement
On an RNAV 1 departure, the system is expected to guide the aircraft along the published path with no more than about a 1-nautical-mile error most of the time.
Intuition Check
RNAV 1 does not mean “one RNAV procedure” or “first-level RNAV.” It means area navigation with a required accuracy of 1 nautical mile.
Example Sentence 1
The departure procedure was charted as RNAV 1, so the crew confirmed the aircraft was properly equipped and the flight plan was loaded correctly before takeoff.
Example Sentence 2
Aircraft approved for RNAV 1 can fly direct segments between waypoints while maintaining the required accuracy.