Definition
A selectable operating mode on an area navigation (RNAV) system used during the final approach phase of an instrument approach. In this mode, the system provides increased course sensitivity and tighter guidance tolerances than the en route or terminal modes, allowing the aircraft to fly a precise track to the runway. On VOR/DME RNAV equipment, selecting approach mode typically narrows the full-scale course deviation indicator (CDI) deflection to a smaller distance per dot, so small lateral deviations show up clearly on the instrument.
Plain English
A setting on the navigation computer that the pilot switches to when flying an instrument approach. It makes the course needle more sensitive, so the aircraft can be flown to the runway with much greater precision than during cruise.
Context Anchor
Seen when using RNAV equipment to fly an instrument approach, especially in discussions of VOR/DME RNAV equipment and approach procedures.
Derivation
RNAV stands for area navigation -- a system that lets an aircraft fly directly between any two points rather than only along VOR airway routes. 'Approach mode' simply means the configuration the equipment is in during the approach phase of flight.
Why Pilots Care
It provides access to instrument approaches at airports that lack ILS, VOR, or NDB facilities, improving safety and utility in low-visibility conditions.
Intuition Check
Do not read “approach” here as simply moving closer to something. In this term, it means the specific instrument approach phase of flight and the equipment setting used for that phase.
Example Sentence 1
Passing the final approach fix, the pilot confirmed the RNAV unit had switched to approach mode and verified the increased CDI sensitivity.
Example Sentence 2
With RNAV approach mode active, the autopilot tracked the curved path to the final approach fix without needing a local VOR signal.