Lateral Navigation

Lateral Navigation (LNAV) is an autopilot and FMS mode that provides automated guidance to keep the aircraft on the planned horizontal (lateral) flight path. When LNAV is engaged, the flight management system commands the autopilot to follow the programmed route, including all waypoints, airways, and transitions, making the necessary turns and track adjustments automatically.

LNAV is one of the two primary navigation modes in the FMS, paired with VNAV (Vertical Navigation) which manages the vertical profile. Together, LNAV/VNAV provide full four-dimensional guidance from departure to arrival.

LNAV is also a type of instrument approach procedure — an LNAV approach provides lateral guidance only (no vertical guidance) using GPS. It is a non-precision approach with step-down fixes and an MDA. Higher levels include LNAV/VNAV (adding barometric vertical guidance) and LPV (using SBAS for precision-like performance).