Narrative:

I programmed FMS to fly summa SID out of sea runway 34L. SID called for tracking out sea R-338 degree to 8 DME, then right turn to 070 degree heading. FMS began turn at about 6 1/2-7 DME to lead turn, taking into account turn radius, instead of flying to 8 DME and then starting turn. I'll have to watch out for this trick next time.

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Original NASA ASRS Text

Title: HDG TRACK DEV ON DEP PROC.

Narrative: I PROGRAMMED FMS TO FLY SUMMA SID OUT OF SEA RWY 34L. SID CALLED FOR TRACKING OUT SEA R-338 DEG TO 8 DME, THEN R TURN TO 070 DEG HDG. FMS BEGAN TURN AT ABOUT 6 1/2-7 DME TO LEAD TURN, TAKING INTO ACCOUNT TURN RADIUS, INSTEAD OF FLYING TO 8 DME AND THEN STARTING TURN. I'LL HAVE TO WATCH OUT FOR THIS TRICK NEXT TIME.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.