MOCA stands for what?

• A. Minimum Offroute Altitude
• B. Minimum Obstruction Clearance Altitude (T)
• C. Minimum Crossing Altitude
• D. Minimum Enroute Altitude

Answer: (B)

MOCA stands for Minimum Obstruction Clearance Altitude. It’s the lowest published altitude that ensures there’s a safe clearance from all obstacles along an IFR route between navigation aids (usually VORs), but with a caveat: this guarantee applies only within 25 nautical miles of a VOR. That means you can rely on MOCA for obstacle clearance on that portion of the route, while outside the 25 NM radius the VOR signal reception can be unreliable, so you’d need other means to navigate. MOCA is different from MEA, which also ensures navigation signal reception along the route beyond 25 NM by the VOR, not just obstacle clearance.