Narrative:

After takeoff; flight directors commanded an unexpected right turn while in IMC and having encountered wake turbulence. As captain; I was expecting a straight-out departure; and said; 'this is not right;' after noticing flight director deflection. First officer was hand flying aircraft and acknowledged my challenge to flight director deflection. During this initial right turn; the tower controller handed us off to the departure controller. Prior to contacting departure control; I requested first officer to make a left turn in reference to my SID chart. First officer complied; and initiated a smooth left turn opting to leave thrust levers in flx/mct. I then contacted departure control; and we were immediately issued a left-turn heading to fly. I selected this heading into the fgcp window and noticed that the flight directors snapped back into an expected and normal position for duration of flight. I was very focused on the flight director movement from this initial moment of deviation; and first officer was still hand flying until certainty of flight directors was established. As deviation to departure SID track was occurring; I was comparing the FD's to confirm a problem; notifying the flying pilot; acknowledging ATC instructions; and ensuring a flight path correction. The first officer was maintaining aircraft stabilization in wake turbulence; attempting to confirm deviation while hand flying in IMC conditions and complying with my request for a left turn just; prior to ATC vectors. While parked at the gate; I had programmed the FMS computer. After further discussion; there is a high probability that I entered runway 1L as the departure runway in the computer flight plan; although the first officer did calculate performance numbers for the 28's. We taxied out to the 28's in a single engine configuration as we were advised to expect a 30-minute delay. We were ultimately parked closer to runway 28L; at the intersection of taxiway left and F. ATC unexpectedly issued us an immediate taxi clearance; in front of an airbus; to runway 28L shortly after. Parallel runway departures were now being used; expediting our queue for takeoff. We picked up the pace of our checklist duties in response. Nearing the end of runway 28L; and expecting to depart soon after a heavy flight ahead; I said to first officer; 'make sure the numbers are all in the box for the left!' I then accepted his response as a confirmation that all departure data was updated and set. While taxiing into position on runway 28L; I quickly glanced at my SID chart and began mentally preparing for the departure. First officer was concerned of traffic landing what appeared to be on our runway. We confirmed this heavy was landing on the parallel; and immediately commenced due to traffic behind us. We then departed behind the heavy ahead of us. Either a problem existed in entering the departure data for takeoff runway; or maintenance manual description of adiru/TCAS 'temporary loss' has occurred. At this time; first officer and I can identify moments during the taxi phase where the scenario potential for incorrect departure data in the FMS was quite probable--primarily towards the end of our departure runway while starting engine #2; rapidly advancing in queue for take-off and accomplishing checklists. A more careful; dual; visual verification of this runway/departure data should have been emphasized even if in a pressured environment.callback conversation with reporter revealed the following information: the reporter stated the taxi from the gate was single engine. Recognizing that their sequence for departure was being expedited; the second engine was started; and checklists were quickly completed. The reporter felt rushed; but when he asked the first officer if all performance data was checked and if they were set up for departure on the left; the response was affirmative. Moderate wake turbulence was encountered after takeoff; and the first officer then initiated a right turn; following the flight director commands. This surprised the reporter and he informed the first officer to turn back to the left for on-course. The event was discussed between the pilots on the subsequent flight; and the reporter now believes that it is likely that the FMS was incorrectly programmed. Anticipating a normal departure; the reporter would have initially selected runway 1L; porte 3 departure. Before takeoff; when queried if the numbers were in the box for the left; the first officer's affirmative response was with regard to the performance data; not the SID and runway selected.

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Original NASA ASRS Text

Title: A320 INITIATED AN UNCOMMANDED RIGHT TURN AFTER TKOF FROM SFO AFTER EXPERIENCING WAKE TURB; RATHER THAN TRACKING THE PROPER COURSE FOR THE PORTE 3 DEP FROM RWY 28L.

Narrative: AFTER TAKEOFF; FLIGHT DIRECTORS COMMANDED AN UNEXPECTED RIGHT TURN WHILE IN IMC AND HAVING ENCOUNTERED WAKE TURBULENCE. AS CAPT; I WAS EXPECTING A STRAIGHT-OUT DEPARTURE; AND SAID; 'THIS IS NOT RIGHT;' AFTER NOTICING FLIGHT DIRECTOR DEFLECTION. FO WAS HAND FLYING AIRCRAFT AND ACKNOWLEDGED MY CHALLENGE TO FLIGHT DIRECTOR DEFLECTION. DURING THIS INITIAL RIGHT TURN; THE TOWER CONTROLLER HANDED US OFF TO THE DEPARTURE CONTROLLER. PRIOR TO CONTACTING DEPARTURE CONTROL; I REQUESTED FO TO MAKE A LEFT TURN IN REFERENCE TO MY SID CHART. FO COMPLIED; AND INITIATED A SMOOTH LEFT TURN OPTING TO LEAVE THRUST LEVERS IN FLX/MCT. I THEN CONTACTED DEPARTURE CONTROL; AND WE WERE IMMEDIATELY ISSUED A LEFT-TURN HEADING TO FLY. I SELECTED THIS HEADING INTO THE FGCP WINDOW AND NOTICED THAT THE FLIGHT DIRECTORS SNAPPED BACK INTO AN EXPECTED AND NORMAL POSITION FOR DURATION OF FLIGHT. I WAS VERY FOCUSED ON THE FLIGHT DIRECTOR MOVEMENT FROM THIS INITIAL MOMENT OF DEVIATION; AND FO WAS STILL HAND FLYING UNTIL CERTAINTY OF FLIGHT DIRECTORS WAS ESTABLISHED. AS DEVIATION TO DEPARTURE SID TRACK WAS OCCURRING; I WAS COMPARING THE FD'S TO CONFIRM A PROBLEM; NOTIFYING THE FLYING PILOT; ACKNOWLEDGING ATC INSTRUCTIONS; AND ENSURING A FLIGHT PATH CORRECTION. THE FIRST OFFICER WAS MAINTAINING AIRCRAFT STABILIZATION IN WAKE TURBULENCE; ATTEMPTING TO CONFIRM DEVIATION WHILE HAND FLYING IN IMC CONDITIONS AND COMPLYING WITH MY REQUEST FOR A LEFT TURN JUST; PRIOR TO ATC VECTORS. WHILE PARKED AT THE GATE; I HAD PROGRAMMED THE FMS COMPUTER. AFTER FURTHER DISCUSSION; THERE IS A HIGH PROBABILITY THAT I ENTERED RUNWAY 1L AS THE DEPARTURE RUNWAY IN THE COMPUTER FLIGHT PLAN; ALTHOUGH THE FO DID CALCULATE PERFORMANCE NUMBERS FOR THE 28'S. WE TAXIED OUT TO THE 28'S IN A SINGLE ENGINE CONFIGURATION AS WE WERE ADVISED TO EXPECT A 30-MINUTE DELAY. WE WERE ULTIMATELY PARKED CLOSER TO RUNWAY 28L; AT THE INTERSECTION OF TAXIWAY L AND F. ATC UNEXPECTEDLY ISSUED US AN IMMEDIATE TAXI CLEARANCE; IN FRONT OF AN AIRBUS; TO RUNWAY 28L SHORTLY AFTER. PARALLEL RUNWAY DEPARTURES WERE NOW BEING USED; EXPEDITING OUR QUEUE FOR TAKEOFF. WE PICKED UP THE PACE OF OUR CHECKLIST DUTIES IN RESPONSE. NEARING THE END OF RUNWAY 28L; AND EXPECTING TO DEPART SOON AFTER A HEAVY FLIGHT AHEAD; I SAID TO FO; 'MAKE SURE THE NUMBERS ARE ALL IN THE BOX FOR THE LEFT!' I THEN ACCEPTED HIS RESPONSE AS A CONFIRMATION THAT ALL DEPARTURE DATA WAS UPDATED AND SET. WHILE TAXIING INTO POSITION ON RUNWAY 28L; I QUICKLY GLANCED AT MY SID CHART AND BEGAN MENTALLY PREPARING FOR THE DEPARTURE. FO WAS CONCERNED OF TRAFFIC LANDING WHAT APPEARED TO BE ON OUR RUNWAY. WE CONFIRMED THIS HEAVY WAS LANDING ON THE PARALLEL; AND IMMEDIATELY COMMENCED DUE TO TRAFFIC BEHIND US. WE THEN DEPARTED BEHIND THE HEAVY AHEAD OF US. EITHER A PROBLEM EXISTED IN ENTERING THE DEPARTURE DATA FOR TAKEOFF RUNWAY; OR MAINTENANCE MANUAL DESCRIPTION OF ADIRU/TCAS 'TEMPORARY LOSS' HAS OCCURRED. AT THIS TIME; FIRST OFFICER AND I CAN IDENTIFY MOMENTS DURING THE TAXI PHASE WHERE THE SCENARIO POTENTIAL FOR INCORRECT DEPARTURE DATA IN THE FMS WAS QUITE PROBABLE--PRIMARILY TOWARDS THE END OF OUR DEPARTURE RUNWAY WHILE STARTING ENGINE #2; RAPIDLY ADVANCING IN QUEUE FOR TAKE-OFF AND ACCOMPLISHING CHECKLISTS. A MORE CAREFUL; DUAL; VISUAL VERIFICATION OF THIS RUNWAY/DEPARTURE DATA SHOULD HAVE BEEN EMPHASIZED EVEN IF IN A PRESSURED ENVIRONMENT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THE TAXI FROM THE GATE WAS SINGLE ENG. RECOGNIZING THAT THEIR SEQUENCE FOR DEP WAS BEING EXPEDITED; THE SECOND ENG WAS STARTED; AND CHECKLISTS WERE QUICKLY COMPLETED. THE REPORTER FELT RUSHED; BUT WHEN HE ASKED THE FO IF ALL PERFORMANCE DATA WAS CHECKED AND IF THEY WERE SET UP FOR DEP ON THE LEFT; THE RESPONSE WAS AFFIRMATIVE. MODERATE WAKE TURB WAS ENCOUNTERED AFTER TKOF; AND THE FO THEN INITIATED A RIGHT TURN; FOLLOWING THE FLT DIRECTOR COMMANDS. THIS SURPRISED THE REPORTER AND HE INFORMED THE FO TO TURN BACK TO THE LEFT FOR ON-COURSE. THE EVENT WAS DISCUSSED BETWEEN THE PLTS ON THE SUBSEQUENT FLT; AND THE REPORTER NOW BELIEVES THAT IT IS LIKELY THAT THE FMS WAS INCORRECTLY PROGRAMMED. ANTICIPATING A NORMAL DEP; THE REPORTER WOULD HAVE INITIALLY SELECTED RWY 1L; PORTE 3 DEP. BEFORE TKOF; WHEN QUERIED IF THE NUMBERS WERE IN THE BOX FOR THE LEFT; THE FO'S AFFIRMATIVE RESPONSE WAS WITH REGARD TO THE PERFORMANCE DATA; NOT THE SID AND RWY SELECTED.

Data retrieved from NASA's ASRS site as of May 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.