What key parameters does VNAV use to determine the vertical path?

VNAV, or Vertical Navigation, primarily relies on altitude constraints, waypoints, and vertical speed to establish and maintain the vertical path of the aircraft. Altitude constraints are critical as they dictate the required altitudes at specific waypoints, ensuring compliance with air traffic control and safe separation between aircraft. Waypoints serve as references in the aircraft's flight plan, allowing VNAV to calculate the optimal vertical profile from one waypoint to the next.

Vertical speed is another essential parameter since it informs the aircraft how quickly it needs to ascend or descend to meet the altitude constraints efficiently. This coordinated use of altitude constraints, waypoints, and vertical speed allows VNAV to provide a smooth and efficient vertical trajectory throughout the flight, helping pilots and autopilot systems manage the aircraft's altitude changes with precision.

While speed, fuel data, weather conditions, air traffic, and aircraft weight can influence flight operations, they are not primary parameters used by VNAV to determine the vertical path. VNAV focuses specifically on the vertical navigation needs dictated by the flight plan.