Lateral Navigation (LNAV)

LNAV (Lateral Navigation) guides the aircraft along a programmed horizontal route between waypoints, typically flown by the autopilot from the flight-management system. Combined with VNAV it lets the aircraft fly a full lateral-and-vertical path with minimal manual input.

Why it matters: lateral navigation is the foundation of area navigation — the aircraft following an arbitrary programmed path rather than radio beacons. It underpins modern routing and every RNAV approach; without it an aircraft is limited to an increasingly legacy navigation environment.

On approaches, the distinction between lateral-only guidance and lateral-plus-vertical matters: LNAV-only minima are higher, so the same runway serves different weather depending on equipment. When evaluating an avionics fit, the practical question is which approach types the installation is actually approved to fly — capability on the box is not approval.