Angle of cut

The angle of cut is the angle at which two position lines intersect on the chart to form a fix. The reliability of the fix depends on this angle: lines crossing near 90 degrees give a tight, robust fix, while a fine angle of cut near 0 or 180 degrees produces a long, error-prone intersection where a small bearing error displaces the fix sharply. Good practice keeps the cut between about 30 and 150 degrees, and a three-bearing fix is spread roughly 60 degrees apart. The principle applies to compass bearings, radar ranges, and mixed range-and-bearing fixes alike.