Definition
A measurable standard for how accurately, reliably, and consistently an aircraft can determine and maintain its position along a defined flight path. Navigation performance is expressed in terms such as required accuracy (often in nautical miles), integrity (the system warns the pilot if it cannot meet that accuracy), continuity (it keeps working through the operation), and availability (it is usable when needed).
Plain English
A way of describing how good an aircraft's navigation has to be for a particular operation -- how close to the centerline it must stay, and how trustworthy the system must be while doing it.
Context Anchor
Seen in instrument procedure discussions, especially when deciding whether the aircraft and its equipment are suitable for a published route, arrival, departure, or instrument approach.
Derivation
Navigation' comes from the Latin navigare, meaning 'to sail a ship.' 'Performance' comes from the Old French parfornir, 'to carry through.' Together the phrase asks a simple question: how well does the navigation actually do its job? In modern aviation that question has been turned into specific, measurable numbers.
Why Pilots Care
It determines whether the aircraft is legally and safely equipped to fly a given RNAV or RNP procedure.
Grounding Statement
Picture the intended flight path as a narrow line through the sky; navigation performance describes how closely the airplane’s navigation system can keep you on that line.
Intuition Check
Do not read “performance” here as engine power, speed, or climb ability. In this context, it means the quality and accuracy of the airplane’s navigation.
Example Sentence 1
Before accepting the RNAV arrival, the crew confirmed the aircraft met the required navigation performance for the procedure.
Example Sentence 2
We checked navigation performance before entering the oceanic airspace to confirm it satisfied the route specifications.