Definition
A navigation system that uses barometric altitude (altitude derived from atmospheric pressure) to provide a computed vertical descent path on certain RNAV instrument approaches. The flight management system or GPS computes a glidepath angle to the runway, and the aircraft's pressure altimeter is used to follow that path. BARO VNAV requires a current local altimeter setting and is subject to a minimum and maximum temperature limit, because non-standard temperatures cause the actual height of the aircraft above the ground to differ from the indicated barometric altitude.
Plain English
A way for the aircraft's computer to fly a steady descent down to the runway by using the altimeter (which measures pressure) instead of a satellite-based vertical signal. The result looks like an ILS-style glidepath on the cockpit display, but the height information comes from air pressure rather than from GPS.
Context Anchor
Seen on RNAV instrument approach charts where vertical guidance is available using the aircraft’s barometric altitude system.
Derivation
Barometric comes from the Greek baros, meaning weight, referring to the weight of the atmosphere measured as pressure. Vertical navigation simply means guidance in the up-down dimension. Together it tells you exactly how the system works: vertical guidance built from pressure-based altitude rather than from GPS height.
Why Pilots Care
It provides stabilized vertical guidance to the runway without needing an ILS glide slope or WAAS vertical capability, increasing access to precision-like approaches at more airports.
Grounding Statement
BARO VNAV is vertical descent guidance built from the same pressure-altitude information that feeds the altimeter.
Intuition Check
Do not assume BARO VNAV measures your exact height above the runway. It uses barometric pressure altitude, so correct settings and chart limits matter.
Example Sentence 1
The crew briefed LNAV/VNAV minimums for the RNAV approach, confirming the temperature was within the published BARO VNAV limits.
Example Sentence 2
With BARO VNAV armed, the autopilot maintained the required descent rate to the decision altitude.