The Minimum Sector Altitude (MSA) is the lowest altitude that ensures at least 300 meters (1,000 feet) of clearance above all objects in a designated area. This area is defined as a sector of a circle with a radius of 46 kilometers (25 nautical miles), centered on a radio navigation aid. MSAs are crucial for safe flight operations and are established for each aerodrome. They guarantee that aircraft maintain a minimum obstacle clearance within that 46 km radius, specifically around the navigation aid or associated approach fixes. It’s important to note that MSA can also refer to Minimum Safe Altitude, which is different from Minimum Sector Altitude. Therefore, it’s essential to clarify which term is being used in any situation.
