What does MSA guarantee in terms of obstacle clearance and range?

• A. MIN SAFE ALT, 25 NM, 1000 FT OBSTACLE CLEARANCE
• B. MSA guarantees 500 ft clearance within 5 NM
• C. MSA guarantees 2000 ft clearance within 15 NM
• D. MSA guarantees 3000 ft clearance within 20 NM

Answer: (A)

MSA (Minimum Safe Altitude) defines a safe altitude in the vicinity of a navigation aid to guarantee obstacle clearance within a 25 nautical mile radius. The standard expectation is at least 1000 feet of obstacle clearance for non-mountainous terrain within that 25 NM circle, with higher clearance (often 2000 feet) noted for mountainous areas on some charts. The option that states minimum safe altitude with a 25 NM radius and 1000 feet of obstacle clearance matches this concept. It reflects the baseline protection pilots rely on when flying near a VOR/NDB to ensure adequate clearance from obstacles within that sector.