Definition
A flight director operating mode in which the command bars on the attitude indicator display steering guidance to keep the aircraft tracking a programmed lateral path, such as an RNAV course, GPS track, or VOR radial. The autopilot, if coupled, follows these commands; if hand-flying, the pilot follows the bars to stay on course.
Plain English
The flight director's command bars are showing the pilot how to steer left or right to stay on the planned course line.
Context Anchor
Seen during area navigation departure setup and instrument departure briefings, when the pilot checks that the flight director will follow the planned path after takeoff.
Derivation
Lateral comes from Latin latus, meaning side. That helps because this mode controls the side-to-side part of navigation: the left and right path, not the up-and-down path.
Why Pilots Care
Reduces pilot workload and improves track accuracy during instrument departures by providing continuous lateral guidance cues.
Intuition Check
Do not read lateral navigation as the airplane moving sideways. Here, lateral means left-right course guidance along the route; it does not provide climb or descent guidance.
Example Sentence 1
After takeoff, the crew confirmed the flight director was in lateral navigation mode and was tracking the RNAV departure course.
Example Sentence 2
With the flight director in lateral navigation mode, the command bars guided the aircraft through the first turn of the procedure.