In the equation W = 2 x d x tan(DF error angle), what does w represent?

• A. Width of the search area in Nautical Miles
• B. Line of bearing
• C. Distance along the great circle
• D. Antenna height

Answer: (A)

The equation shows that the width of the search area at a given distance comes from basic trigonometry: at distance d from the centerline, an angular error creates a wedge on each side whose half-width is d tan(angle). Doubling that gives the full width, W = 2 d tan(angle). Since d is in nautical miles and tan(angle) is dimensionless, the result is in nautical miles, representing how wide the search corridor is at that range. The other options don’t describe a cross‑track width: a line of bearing is a direction, distance along a great circle is a curved path length, and antenna height relates to elevation, not the search belt width.