Definition
A flight director or autopilot mode that automatically captures and tracks a selected navigation course, such as a VOR radial or GPS course, by computing and flying the appropriate intercept angle from the aircraft's current position.
Plain English
A mode that lets the autopilot or flight director steer the airplane onto a chosen navigation course on its own, then follow that course once it gets there.
Context Anchor
Seen when using flight director or autopilot navigation mode, often after using heading guidance to aim the airplane toward the desired course.
Derivation
"Intercept" comes from Latin intercipere, meaning "to seize between" or "catch on the way." In navigation, the aircraft is being caught and turned onto the course as it crosses it.
Why Pilots Care
Ensures the autopilot captures the desired course smoothly without overshoot, which is essential for safe instrument navigation and reduced pilot workload.
Intuition Check
Do not read intercept as simply crossing a line. In this context, it means joining the selected navigation course so the airplane can follow it.
Example Sentence 1
After takeoff, the pilot selected NAV intercept so the autopilot would capture the published departure course once the aircraft was established on the assigned heading.
Example Sentence 2
During the approach briefing the crew discussed the expected NAV intercept point onto the final approach course.