Automatic Radar Plotting Aids (ARPA) 2025 – 400 Free Practice Questions to Pass the Exam

The required range scales for ARPA (Automatic Radar Plotting Aids) facilities are critical for effectively monitoring and managing maritime traffic. Selecting appropriate range scales allows operators to maintain situational awareness and make informed navigational decisions.

The typical range scales must ensure that the radar can accurately track and predict the movement of targets, particularly as vessels approach or move away from the radar installation. The chosen scales need to cover a spectrum that includes close-range operations as well as more extended ranges to cater to various navigation scenarios.

The range scales of three or four miles and 12 or 16 miles are ideal because they balance the need for detail at close range with the capacity to monitor longer distances. This helps in identifying potential collision risks and ensuring safe navigation in busy shipping lanes or congested waterways.

In contrast, other options either do not provide adequate resolution at shorter distances or do not extend enough for longer-range tracking. Understanding these requirements is essential for effective radar use, alignment with international standards, and compliance with safety protocols in navigational operations.