Blaze Through the Fire Support Team (FIST) Challenge 2025 – Ignite Your Certification Success!

An OF fan, or Observed Fire fan, is a graphical representation used in artillery and fire support operations to visually depict the coverage area of an observer’s target engagement options. Each radial arm in an OF fan represents a specific angle at which fire can be directed.

The key detail in the question is that the arms are 100 mils apart and cover a total of 1,600 mils. To determine the number of radial arms in the fan, you need to divide the total coverage of 1,600 mils by the spacing between the arms, which is 100 mils.

When you perform this calculation, you find that 1,600 mils divided by 100 mils equals 16. However, since the radial arms define the boundaries of the fan rather than the actual number of arms. The first arm starts at 0 mils, and so there will be a total of 17 arms from 0 to 1600 mils to include both the starting point and the endpoint.

Thus, the correct answer is that an OF fan has 17 radial arms that are each 100 mils apart and collectively cover a span of 1,600 mils.