Quadrantal error in a gyrocompass has its GREATEST effect on which of the following?

Correct Answer: Option B — on intercardinal headings

Quadrantal error is caused by horizontal soft iron near the compass. According to Bowditch, this error is a function of the sine and cosine of twice the compass heading. Consequently, the error is zero on cardinal headings and reaches its maximum magnitude on intercardinal headings (NE, SE, SW, NW).