Hi all For XML fs9 Busy with descent profiles and am struggling with converting this formula for XML to get distance from VB track in feet. XTD =asin(sin(dist_AD)*sin(crs_AD-crs_AB)) Can anyone help.

Are asin, sin, etc defined XML functions?

Ed Yes, They are listed in the SDK Paul

Hi Paul,This should work:crs_AD crs_AB - sin dist_AD sin * asin (>YourLVar)Tom

After paying more attention to your formula, sin(dist_AD) seems to be wrong because dist_AD is precisely a distance, not an angle. Are you sure that formula is right?BTW I use this one to obtain a certain crosstrack error:PLANE_TO_WPT distance (nmiles, feet)DESIRED TRACK (radians)PLANE_TO_BEARING (radians)- sin * (>LCrossTrackError) (nmiles,feet)Maybe you can take it as a reference.Tom

Tom It's a crosstrack formula from this site http://williams.best.vwh.net/avform.htm#Intro With lots of good aviation stuff that goes over my head. Thanks I'll try and adapt your code. Paul

Tom Got it @TotalDistRem 16 - 6076.13 * s1 0.064577 (A:Indicated Altitude, feet) @EndDecsentAlt - l1 / tg - sin * Thanks for the help Paul