Definition
A vertical navigation system that uses barometric altitude information from the aircraft's air data computer, combined with lateral guidance from an RNAV (typically GPS) source, to generate a computed vertical descent path on certain instrument approaches. The flight management system calculates a glidepath to the runway and displays vertical deviation guidance to the pilot, allowing a stabilized descent to a published decision altitude rather than a step-down approach.
Plain English
A way for the aircraft's computer to fly a smooth, sloped descent to the runway by using the altimeter to know how high it is and the GPS to know where it is. Instead of stepping down level by level, the pilot follows a continuous descent path shown on the instruments.
Context Anchor
Seen on instrument approach charts, especially RNAV (GPS) approaches with LNAV/VNAV minimums or notes about Baro-VNAV temperature limits.
Derivation
Baro is short for barometric, meaning pressure-based. VNAV stands for Vertical Navigation. The name signals that the vertical path is computed using pressure altitude, not a ground-based signal like an ILS glideslope or a satellite-based geometric height.
Why Pilots Care
It provides stabilized descent guidance on RNAV approaches for aircraft without WAAS, reducing the risk of unstabilized approaches.
Grounding Statement
On final approach, Baro-VNAV uses the aircraft’s sensed altitude to show whether the airplane is above or below the planned descent path.
Intuition Check
Do not assume Baro-VNAV is the same as an ILS glide slope or a satellite-generated glide path. The key point is “baro”: the vertical guidance is based on barometric altitude.
Example Sentence 1
Because the outside air temperature was below the charted minimum, the crew could not use the LNAV/VNAV line and flew the approach to LNAV minimums instead of using Baro-VNAV.
Example Sentence 2
Using Baro-VNAV, the aircraft maintained the published glidepath angle down to the decision altitude.