Drift angle is the difference between true heading and track measured either left or right of
true heading. The aircraft will drift off-course to the left due to the northeasterly wind
blowing from 030 at 30 knots (030/30). Instead of accepting this off-course drift, the
aircraft must be turned into the wind to compensate for the right crosswind.
Crab angle is the amount of correction an aircraft must be turned into the wind in order to
maintain the desired course. It is equal in magnitude but in opposite in direction, to the Drift
Angle (Figure 4.5-8).
If given any two sides of the wind triangle, the third side can be found by using the CR-3
Figure 4.5-8 Crab Angle