What does MOCA stand for?

Minimum Obstruction Clearance Altitude, or MOCA, is a critical concept in aviation that indicates the lowest altitude at which a pilot can fly in the vicinity of obstructions, ensuring safe vertical clearance. This altitude guarantees that an aircraft will remain clear of obstacles in the area while also providing navigational signal coverage for the aircraft's navigation aids like VORs (VHF Omnidirectional Range stations).

MOCA is particularly important when flying off airways, as it allows pilots to safely navigate terrain and structures while still adhering to minimum altitude requirements. It is calculated based on the highest obstruction in the area and adds an additional buffer to ensure safety.

While the other options present terms that sound plausible within the context of aviation altitudes, they do not correctly define MOCA. Understanding the significance of MOCA is essential for instrument flight operations, enabling pilots to maintain safety while optimizing their flight paths.