Narrative:

I called ground for taxi instructions. They advised new departure frequency, taxi to runway 7L. As we taxied, I reprogrammed the computer for runway 7L. It had already been set up at the gate for runway 25R verified by both legs and plan page. As I reprogrammed for runway 7L, I visually checked the map. It looked good and executed it. Then the captain had given the normal takeoff briefing (initial altitude, heading, engine out and special procedures). We departed with normal calls and at 400 ft I asked for LNAV, following the pink and climbing to 7000 ft. At approximately 6100 ft, we got a TCASII TA/RA. I continued to fly and then ATC asked if our RNAV had brought us off course. I quickly went to raw data to check and we were left of course. I then turned to a 090 degree heading. ATC then asked us to take up a 110 degree heading. While this occurred, 7000 ft came and went. I instantaneously brought the plane back to assigned atl and turned the autoplt on. At this point, ATC then had given us clearance to next fix (tralr) and on course, also switching us to ZLA. Before switching, the captain said, 'sorry about the error.' ATC responded 'thanks, no problem.' I, being complacent, should have checked the legs and plan page prior to using the LNAV! Supplemental information from acn 632728: while climbing out, we first noticed a TCASII traffic alert (not an RA,) and became involved with locating the close proximity traffic. My short take on what happened: my best guess is that when the runway change was made during taxi out, the FMC dropped the departure procedure and gave us a course to our first en route fix. This new course took us to the left of the RNAV departure procedure course.

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Original NASA ASRS Text

Title: A B757 FLT CREW FAIL TO CATCH ERROR IN THE FMS RESULTING IN BEING OFF COURSE AND GETTING A TCASII TA.

Narrative: I CALLED GND FOR TAXI INSTRUCTIONS. THEY ADVISED NEW DEP FREQ, TAXI TO RWY 7L. AS WE TAXIED, I REPROGRAMMED THE COMPUTER FOR RWY 7L. IT HAD ALREADY BEEN SET UP AT THE GATE FOR RWY 25R VERIFIED BY BOTH LEGS AND PLAN PAGE. AS I REPROGRAMMED FOR RWY 7L, I VISUALLY CHKED THE MAP. IT LOOKED GOOD AND EXECUTED IT. THEN THE CAPT HAD GIVEN THE NORMAL TKOF BRIEFING (INITIAL ALT, HDG, ENG OUT AND SPECIAL PROCS). WE DEPARTED WITH NORMAL CALLS AND AT 400 FT I ASKED FOR LNAV, FOLLOWING THE PINK AND CLBING TO 7000 FT. AT APPROX 6100 FT, WE GOT A TCASII TA/RA. I CONTINUED TO FLY AND THEN ATC ASKED IF OUR RNAV HAD BROUGHT US OFF COURSE. I QUICKLY WENT TO RAW DATA TO CHK AND WE WERE L OF COURSE. I THEN TURNED TO A 090 DEG HDG. ATC THEN ASKED US TO TAKE UP A 110 DEG HDG. WHILE THIS OCCURRED, 7000 FT CAME AND WENT. I INSTANTANEOUSLY BROUGHT THE PLANE BACK TO ASSIGNED ATL AND TURNED THE AUTOPLT ON. AT THIS POINT, ATC THEN HAD GIVEN US CLRNC TO NEXT FIX (TRALR) AND ON COURSE, ALSO SWITCHING US TO ZLA. BEFORE SWITCHING, THE CAPT SAID, 'SORRY ABOUT THE ERROR.' ATC RESPONDED 'THANKS, NO PROB.' I, BEING COMPLACENT, SHOULD HAVE CHKED THE LEGS AND PLAN PAGE PRIOR TO USING THE LNAV! SUPPLEMENTAL INFO FROM ACN 632728: WHILE CLBING OUT, WE FIRST NOTICED A TCASII TFC ALERT (NOT AN RA,) AND BECAME INVOLVED WITH LOCATING THE CLOSE PROX TFC. MY SHORT TAKE ON WHAT HAPPENED: MY BEST GUESS IS THAT WHEN THE RWY CHANGE WAS MADE DURING TAXI OUT, THE FMC DROPPED THE DEP PROC AND GAVE US A COURSE TO OUR FIRST ENRTE FIX. THIS NEW COURSE TOOK US TO THE L OF THE RNAV DEP PROC COURSE.

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.