A Monroe ATCT nonradar departure must NOT be cleared above 6,000 feet until:

The correct answer emphasizes that an aircraft departing from Monroe ATCT in nonradar conditions must be cleared above 6,000 feet only after it is established on the ARTCC-assigned route. This requirement is crucial for maintaining safe and efficient air traffic management.

When an aircraft departs without radar coverage, it is essential to ensure that it follows a precise route to minimize the risk of altitude or geographical conflicts with other aircraft and to maintain safe separation distances. By ensuring the aircraft is established on the assigned route, controllers can better predict its flight path and descent requirements while keeping other air traffic safely separated.

This procedural step is vital in nonradar environments, where the lack of real-time tracking makes it more difficult to provide the same level of oversight and control that radar would typically facilitate. Therefore, confirming that the aircraft is on the correct route before allowing it to ascend beyond 6,000 feet aligns with safety protocols and air traffic management efficiency.