Appendix 3 to ETSO-C117b - Wind Field Model Coordinate System Transformation

• ED Decision 2020/011/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

###### Appendix 3 to ETSO-C117b – Wind Field Model Coordinate System Transformation *ED Decision 2020/011/R* This Appendix describes the conversion of the velocity equations in Appendix 2 to rectangular coordinates. Define intermediate variables to simplify written equations: Horizontal and Vertical Velocities Partial Derivatives Other Relationships From TASS Maximums (λ is determined from the above relationships) Variable List z\* = altitude where wx is half the value of wx max (ft) ε = characteristic height of boundary layer effects (ft) zh = depth of outflow (ft) zm = altitude of maximum outflow (ft) λ = scaling parameter (s-1) r = radial distance from aeroplane to downburst (ft) h = altitude of aeroplane (ft) R = radius of downdraft (ft) xad, yad = x, y coordinates, aeroplane to microburst (ft) wx max, wy max, wh max maximum winds, x, y, and h directions [Amdt ETSO/16]