What systems do most aircraft utilize for VNAV?

The correct choice for the systems most aircraft utilize for vertical navigation (VNAV) is Flight Management Systems (FMS) or Advanced Avionics. FMS is an integrated system that assists pilots in navigation and flight planning, providing precise control over the vertical navigation aspects of flight. These systems utilize a combination of GPS, inertial navigation, and other data sources to calculate and maintain the desired altitude profile during different phases of flight, including climbs, descents, and level flight.

Advanced avionics typically include not only FMS but also functionalities that facilitate automation in managing altitude and speed in accordance with flight plans and air traffic control instructions. This automation helps improve efficiency and safety, allowing pilots to focus on other critical aspects of flight operations.

While manual navigation systems, basic analog instruments, and visual flight rules (VFR) guidance play roles in piloting aircraft, they do not offer the comprehensive automated capabilities for VNAV that FMS and modern avionics provide. Manual systems are more reliant on pilot input and decision-making, and basic instruments might not have the necessary technology to effectively manage vertical navigation in contemporary aviation. Similarly, VFR guidance is primarily intended for visual navigation and does not support the levels of precision required for vertical navigation, particularly in instrument flight