Narrative:

We programmed our flight management computer for our cleared route including the SID (border four departure). Both first officer and myself double-checked the route and both of us confirmed it as correct. Departure runway was runway 27. At approximately 400 ft, the first officer called for autoplt #2 on. I selected autoplt #2 on. On my FMA, 'navigation engaged and autoplt #2 on.' however, at this point the aircraft began a turn to the left. This departure requires a heading of 270 degrees until reaching the pgy 19 DME. I noticed something was wrong and I told first officer to disconnect the autoplt and turn the aircraft to the right to heading of 275 degrees. I selected 275 degree heading on flight control unit and we turned to 275 degrees. At this point, we were slightly left of a normal departure track. On our navigation displays, we had all of our waypoints displayed, but no course line to connect the waypoints. We flew the departure manually until we were able to establish a course line on our navigation displays. Once cleared to the next fix, we were able to establish normal navigation capabilities. Looking back, I remember our course line being there just prior to takeoff. Sometime between takeoff and 400 ft the fault occurred. We checked our secondary flight plan and it contained the exact departure data so no error was made in entry. San diego is very noise sensitive, so strict adherence to the departure is a must. We were slightly south of the normal path. Once the aircraft begins a turn it takes a bit to turn it the opposite way. Currently searching for an answer from technicians. Our somewhat erratic track was not mentioned by ATC (socal departure or san diego tower).

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Original NASA ASRS Text

Title: A319 CREW HAD TRACK DEV DEPARTING SAN RWY 27.

Narrative: WE PROGRAMMED OUR FLT MGMNT COMPUTER FOR OUR CLRED RTE INCLUDING THE SID (BORDER FOUR DEP). BOTH FO AND MYSELF DOUBLE-CHKED THE RTE AND BOTH OF US CONFIRMED IT AS CORRECT. DEP RWY WAS RWY 27. AT APPROX 400 FT, THE FO CALLED FOR AUTOPLT #2 ON. I SELECTED AUTOPLT #2 ON. ON MY FMA, 'NAV ENGAGED AND AUTOPLT #2 ON.' HOWEVER, AT THIS POINT THE ACFT BEGAN A TURN TO THE L. THIS DEP REQUIRES A HEADING OF 270 DEGS UNTIL REACHING THE PGY 19 DME. I NOTICED SOMETHING WAS WRONG AND I TOLD FO TO DISCONNECT THE AUTOPLT AND TURN THE ACFT TO THE R TO HEADING OF 275 DEGS. I SELECTED 275 DEG HDG ON FLT CTL UNIT AND WE TURNED TO 275 DEGS. AT THIS POINT, WE WERE SLIGHTLY L OF A NORMAL DEP TRACK. ON OUR NAV DISPLAYS, WE HAD ALL OF OUR WAYPOINTS DISPLAYED, BUT NO COURSE LINE TO CONNECT THE WAYPOINTS. WE FLEW THE DEP MANUALLY UNTIL WE WERE ABLE TO ESTABLISH A COURSE LINE ON OUR NAV DISPLAYS. ONCE CLRED TO THE NEXT FIX, WE WERE ABLE TO ESTABLISH NORMAL NAV CAPABILITIES. LOOKING BACK, I REMEMBER OUR COURSE LINE BEING THERE JUST PRIOR TO TKOF. SOMETIME BTWN TKOF AND 400 FT THE FAULT OCCURRED. WE CHKED OUR SECONDARY FLT PLAN AND IT CONTAINED THE EXACT DEP DATA SO NO ERROR WAS MADE IN ENTRY. SAN DIEGO IS VERY NOISE SENSITIVE, SO STRICT ADHERENCE TO THE DEP IS A MUST. WE WERE SLIGHTLY S OF THE NORMAL PATH. ONCE THE ACFT BEGINS A TURN IT TAKES A BIT TO TURN IT THE OPPOSITE WAY. CURRENTLY SEARCHING FOR AN ANSWER FROM TECHNICIANS. OUR SOMEWHAT ERRATIC TRACK WAS NOT MENTIONED BY ATC (SOCAL DEP OR SAN DIEGO TWR).

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.