What provides a minimum of 300 feet obstacle clearance during circling approaches?

The Circling Minimum Descent Altitude (MDA) is the altitude to which a pilot can descend during a circling approach while still maintaining the required obstacle clearance, which is a minimum of 300 feet above the highest obstacle within the specified circling area. This MDA ensures that the aircraft remains at a safe altitude until a visual reference to the runway is established, allowing for a safe transition to landing.

During circling approaches, pilots need to be aware of terrain and obstacles surrounding the intended flight path, and the MDA is specifically defined in the approach procedures to provide that necessary margin of safety. It helps pilots avoid potential collisions with obstacles while they maneuver to land.

In contrast, decision height is an altitude used in precision approaches, minimum safe altitude pertains to enroute navigation, and height above threshold relates more to the final approach phase rather than the circling phase. Understanding the role of MDA in circling approaches is crucial for maintaining safety during instrument flight operations in areas with obstacles.