Which of the following pairs is correctly matched?

• A. MEA - Minimum enroute altitude
• B. MCA - Minimum crossing altitude
• C. MDA - Minimum descent altitude
• D. MOCA - Minimum safe altitude

Answer: (B)

Understanding IFR altitude acronyms is about knowing where and why each altitude applies. Minimum Crossing Altitude is the altitude you must be at when crossing a specific fix or intersection to ensure obstacle clearance for that segment. It’s set so you can safely proceed beyond the crossing point.

The other terms have different roles. Minimum Enroute Altitude is designed to guarantee obstacle clearance and reliable navigation reception along a route between nav aids, not at a single crossing fix. Minimum Descent Altitude is the lowest altitude you may descend to on a non-precision approach before the runway environment is in sight, not a crossing requirement. Minimum Obstacle Clearance Altitude provides obstacle clearance for the route segment as a whole, but it also carries a nav-reception caveat: reception is guaranteed only within 25 nautical miles of the aiding facility, and it is not a crossing altitude.