The E6BJA Visualiser uses the Wind Correction Angle (WCA) and Ground Speed (GS) calculations and plots them on the compass rose together with a Diversion Star within the rose. This enables pilot input of the TAS (True Air Speed), intended Course/Track and the Wind Vector (wind direction and speed) which then go to compute the Heading to fly and Ground Speed.
Diversions and Diversion Star
Diversions often require a new Wind Correction Angle and Ground Speed to be calculated from the wind direction and new track to the diversion fix. The Diversion Star automatically and instantaneously calculates the Wind Correction Angles (Teal) and Ground Speeds (Purple) for each of
the cardinal compass directions (as well as NE, SE, SW, NW) based on the input Wind Vector and TAS (True Air Speed).
An alternative is to use the MDA (Maximum Drift Angle) — the worse case Wind Correction Angle, as if the wind was blowing orthogonally to the aircraft's track. In this way, the MDA is calculated pre-flight (it can also be re-computed in-flight given a revised Wind Vector), and once a diversion is chosen, the Acute Wind Angle (the angle between the wind direction and diversion track) is used, applying the Clock Code — the Clock Code selects a proportion of the MDA to use as the WCA for the diversion track.