+Where `PacketIndex` indicates something like a schema version, i.e. what each
+of the numbered groups means. For example, in X-Plane 10, packet index is 64
+(character `"@"`) and group 3 contains speed data, in which the 8 group values
+are:
+
+| Location | Label | Description |
+|----------|---------------|-------------|
+| 1 | `vind_kias` | Velocity indicated, in knots indicated airspeed. |
+| 2 | `vind_keas` | Velocity indicated, in knots equivalent airspeed (the calibrated airspeed corrected for adiabatic compressible flow at the craft's current altitude). |
+| 3 | `vtrue_ktas` | Velocity true (the speed of the craft relative to undisturbed air), in knots true airspeed. |
+| 4 | `vtrue_ktgs` | Velocity true, in knots true ground speed. |
+| 5 | | Unused. Contains a dummy value. |
+| 6 | `vind_mph` | Velocity indicated, in miles per hour. |
+| 7 | `vtrue_mphas` | Velocity true, in miles per hour airspeed. |
+| 8 | `vtrue_mphgs` | Velocity true, in miles per hour ground speed. |
+
+
+References
+----------