What area does the Minimum Safe Altitude (MSA) cover and how much obstacle clearance does it provide?

The Minimum Safe Altitude (MSA) is designed to ensure that aircraft maintain a safe altitude above terrain and obstacles in the vicinity of a navigation aid or the route being flown. An important aspect of MSA is that it provides both a specific radius for the area of coverage and an established vertical buffer to ensure safety.

In the case of the correct choice, the MSA covers an area of 25-30 nautical miles around the specified navigation aid, which is crucial for flight safety in areas where obstacles such as terrain or man-made structures could pose a risk. The altitude provided gives a minimum clearance of 1,000 feet above the highest obstacle within that radius, significantly reducing the risk of accidents during flight operations.

The choice accurately reflects the typical standards used in aviation for MSA, where a clearance of 1,000 feet is commonly prescribed. This altitude provides a sufficient margin to account for variations in terrain and ensures safe navigation for aircraft, especially during instrument flight rules (IFR) operations.