Definition
An autopilot or flight director mode that automatically steers the aircraft to track a selected navigation course, such as a VOR radial, GPS course, or RNAV flight plan leg. When engaged, the system uses inputs from the navigation receiver to keep the aircraft on the chosen course without continuous manual heading adjustments by the pilot.
Plain English
A setting on the autopilot that tells the aircraft to follow a chosen course line by itself, instead of you hand-flying it onto that line.
Context Anchor
Seen in helicopter flight manual limitations and instrument flying procedures when discussing approved use of flight guidance or autopilot functions.
Derivation
NAV is a shortened form of navigation, meaning finding and following a route. Mode means a selected way a system operates. Together, NAV mode means the system is operating in its navigation-following state.
Why Pilots Care
Enables accurate, low-workload navigation but is subject to specific flight manual limitations that must be observed for safe operation.
Intuition Check
NAV mode does not mean the aircraft is handling the whole flight for you. It only means the selected system is using a navigation source to give or follow course guidance.
Example Sentence 1
After intercepting the final approach course, the pilot engaged NAV mode and the autopilot tracked the course inbound.
Example Sentence 2
Helicopter flight manual limitations prohibited use of NAV mode during the final segment of the approach.