VNAV

VNAV (Vertical Navigation) is the autopilot/FMS mode that provides automated vertical flight path guidance, computing and following the optimal climb, cruise, and descent profile based on performance data, constraints, and cost index.

• VNAV PTH (Path): Follows a computed vertical path — adjusts thrust to stay on profile
• VNAV SPD (Speed): Maintains a target speed — vertical path may deviate
• VNAV ALT: Captures and holds a selected altitude
• VNAV computes Top of Descent (TOD) point for optimal descent initiation
• Respects altitude and speed constraints from SIDs, STARs, and approach procedures
• Works in conjunction with LNAV for fully coupled 3D navigation
• Baro-VNAV provides vertical guidance for approaches without ILS (LPV approaches use SBAS instead)