If signals from an off-airway radio facility are inadequate to identify the fix at the designated MEA, which altitude should be used for the fix?

The Minimum Reception Altitude (MRA) is the correct altitude to use in this scenario. The MRA is defined as the lowest altitude at which adequate reception of navigational signals can be expected for an off-airway radio facility. If the signals from the facility are inadequate at the Minimum Enroute Altitude (MEA), it is essential to climb to the MRA to ensure reliable navigation and communication, enabling accurate identification of the fix.

In contrast, the Minimum Crossing Altitude (MCA) is typically used for safely crossing obstructions on an airway and is often specified for certain segment transitions, rather than for signal reception issues. The Minimum Obstacle Clearance Altitude (MOCA) provides a specified level of terrain clearance within a specific distance from the VOR, but it does not inherently ensure adequate signal coverage. The Maximum Authorized Altitude (MAA) relates to the maximum altitude you can fly on a route segment without risking signal interference, which is not applicable to this situation.

Understanding the roles of these different altitudes in navigation allows pilots to make informed decisions when navigating in conditions where signal reception is compromised.