minimum obstacle clearance altitude (MOCA)

The lowest published altitude in effect between radio fixes on VOR (very high frequency omnidirection radio-range) airways, off-airway routes, or route segments that meets obstacle clearance requirements for the entire route segment and ensures acceptable navigational signal coverage only of a VOR. In the United States and some other countries, this coverage is only within 22 NM of a VOR. It is depicted on aeronautical charts as shown in the illustration.

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References in periodicals archive

The MSA is the minimum obstacle clearance altitude surrounding identified fixes (and not always the airport or the final approach fix, so watch out) and is further defined by radials or bearings and distances from that fix.

Let yourself down: verify the altitude to which you can descend before pulling the plug. Even if you're off airways or being vectored, you'll find it on the chart

An airway segment capped with a "T" indicates a MEA or Minimum Obstacle Clearance Altitude (MOCA) change.

Mile-high migraine: it may take more than circling the wagons and a dose of tylenol to ease your headache as you solve this killer quiz

The minimum obstacle clearance altitude (MOCA) provides the obstacle clearance of the MEA, but not necessarily the ground-based navaid reception more than 25 miles from the beacon.

Non-radar IFR: once you're off the beaten path, ATC can't see you or provide the services--like obstacle clearance--we've taken for granted. They're now your responsibility

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