Narrative:

On receiving my clearance from apc-las; I was given: departing runway 18R direct sgd right turn direct lidat then as filed. I then entered the plan into the FMS which does not take into account turning directions of greater than 180 degrees. Basically; the FMS turns the direction that would be a shorter turn to the next fix. After takeoff; I turned directly to sgd and queried norcal departure as to my immediate clearance. The controller immediately told me to fly direct sgd then right turn lidat. During this climb out a fuel imbal issue arose that took my attention off the navigation from sgd to lidat. Consequently; as I crossed over sgd the FMS turned left instead of right to lidat. I realized what had happened just as norcal approach brought it to my attention. No conflict was readily apparent to me as I feel the controller was coordinating my error with another sector. I feel this event was completely my fault as I allowed myself to be distraction with less than critical events. The only idea I have as to preventing this type of mistake in the future would be to have a published departure procedure in place. This visual aid may create a visual trigger as to turning directions greater than 180 degrees.

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Original NASA ASRS Text

Title: A P180 ON DEP FROM APC DEVIATED FROM CLRED TRACK WHEN THE AUTOPLT TURNED SHORTEST DIRECTION RATHER THAN CLRED DIRECTION.

Narrative: ON RECEIVING MY CLRNC FROM APC-LAS; I WAS GIVEN: DEPARTING RWY 18R DIRECT SGD R TURN DIRECT LIDAT THEN AS FILED. I THEN ENTERED THE PLAN INTO THE FMS WHICH DOES NOT TAKE INTO ACCOUNT TURNING DIRECTIONS OF GREATER THAN 180 DEGS. BASICALLY; THE FMS TURNS THE DIRECTION THAT WOULD BE A SHORTER TURN TO THE NEXT FIX. AFTER TKOF; I TURNED DIRECTLY TO SGD AND QUERIED NORCAL DEP AS TO MY IMMEDIATE CLRNC. THE CTLR IMMEDIATELY TOLD ME TO FLY DIRECT SGD THEN R TURN LIDAT. DURING THIS CLBOUT A FUEL IMBAL ISSUE AROSE THAT TOOK MY ATTN OFF THE NAV FROM SGD TO LIDAT. CONSEQUENTLY; AS I CROSSED OVER SGD THE FMS TURNED L INSTEAD OF R TO LIDAT. I REALIZED WHAT HAD HAPPENED JUST AS NORCAL APCH BROUGHT IT TO MY ATTN. NO CONFLICT WAS READILY APPARENT TO ME AS I FEEL THE CTLR WAS COORDINATING MY ERROR WITH ANOTHER SECTOR. I FEEL THIS EVENT WAS COMPLETELY MY FAULT AS I ALLOWED MYSELF TO BE DISTR WITH LESS THAN CRITICAL EVENTS. THE ONLY IDEA I HAVE AS TO PREVENTING THIS TYPE OF MISTAKE IN THE FUTURE WOULD BE TO HAVE A PUBLISHED DEP PROC IN PLACE. THIS VISUAL AID MAY CREATE A VISUAL TRIGGER AS TO TURNING DIRECTIONS GREATER THAN 180 DEGS.

Data retrieved from NASA's ASRS site as of January 2009 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.