In a nine-line format, which lines must always be read back for elevation and coordinates?

• A. Line 3 and Line 5
• B. Line 4: Elevation and Line 6: Coordinates
• C. Line 2 and Line 9
• D. Line 1 and Line 7

Answer: (B)

Reading back data that determines where and how high a round will go is essential in a nine-line fire mission. The line that carries the elevation value and the line that carries the target coordinates are the two pieces of numeric data most critical to get exactly right. Elevation sets the ballistic angle, while coordinates fix the target location on the map. If either is misheard or mistyped, the round could miss, land in the wrong area, or cause unintended harm. Repeating these two data fields back confirms both sides have the same values and protects against radio errors.