VNAV operations in the terminal area are prohibited when the ceiling is less than what value?

• A. 500' AGL
• B. 1000' AGL
• C. 1500' AGL
• D. 2000' AGL

Answer: (B)

VNAV in the terminal area relies on a safe, defined vertical path that assumes enough ceiling to maintain obstacle clearance and allow the crew to manage the descent with adequate visual or procedural support. When the ceiling drops below 1000 ft AGL, that margin is no longer guaranteed, making automated vertical guidance risky during approaches and transitions in busy terminal airspace. To protect against insufficient clearance and potential maneuvering surprises, VNAV in the terminal area is prohibited under 1000 ft AGL.

Lower values, like 500 ft AGL, would leave even less room for error and are not allowed, while higher ceilings (1500 or 2000 ft) aren’t the established operational threshold for this rule. If ceilings are under 1000 ft, pilots would revert to non-VNAV procedures and manual altitude control as appropriate.