Narrative:

Third leg of a 4 leg, 5 day identify. Scheduled rest of approximately 13 hours, block-to-block. Relatively short flying time planned for 1 hour 45 min en route. During our predep briefing, the captain and I thoroughly discussed the engine-out procedure, the radio-out procedures (and how they were alike), and the SID. We talked about the reasons for the engine-out/radio-out part of which is the terrain, but also because of the restr areas designed to keep you from flying into the no-man's-land/free fire zone a few mi north. The WX was good/clear, with not much wind. On the runway, the captain gave me the airplane, and we got clearance for takeoff. Normal takeoff till about 500 ft, where I announced that I was starting my left turn. I don't know if the left turn was caught by the captain. Since the WX was clear, we were both looking out, not only for traffic, but for the landmarks concerning the restr area (free fire zones), and the terrain, which required the engine-out/lost communications procedures. Unfortunately, the SID did not require a left turn at that point. The captain caught the error after I was established in the turn, about the same time as I did. We were in a turn back to the right, when departure control requested our heading, and gave us a turn to 220 degrees. There was no other traffic on takeoff or on approach to either runway, whom we might have interfered with. After established in the climb and on headings, departure asked why we deviated. The captain said that there was an error in using the FMC, not sure the exact words. I was kind of in shock at what just occurred! Departure asked if there were any further problems, and the captain assured him that there were none. There was no further discussion on the deviation with ATC. I apologized for the error and confessed I had no clue as to why. Later the captain said he would fill out a report. I made the assumption (false!) that it was for both of us. I don't know why I made the turn early, considerably early. It might have been something to do with the restr areas. There is nothing that I am consciously aware of. Believe me, I have searched. I know that in flying tag legs for over a yr, I still don't get good rest the night before this leg. This night was no better. Got a couple of hours of incomplete sleep, though I was in bed for 8 hours with lights out. The time of takeoff is usually (home/body time) about 2 hours before my regular go-to-bed/sleep routine. However, I don't recall being sleep deprived at this time. Also, thought about the impact of our company problems. I have tried to not let them interfere with my performance. There is almost no influence any of us have on the ultimate (and unknown) outcome. I can't put my finger on anything like that. But, I can't guarantee there is no impact.

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Original NASA ASRS Text

Title: B777 FLT CREWBEGINS REQUIRED TURN ON RNAV DEP EARLY WHILE DEPARTING KSI.

Narrative: THIRD LEG OF A 4 LEG, 5 DAY IDENT. SCHEDULED REST OF APPROX 13 HRS, BLOCK-TO-BLOCK. RELATIVELY SHORT FLYING TIME PLANNED FOR 1 HR 45 MIN ENRTE. DURING OUR PREDEP BRIEFING, THE CAPT AND I THOROUGHLY DISCUSSED THE ENG-OUT PROC, THE RADIO-OUT PROCS (AND HOW THEY WERE ALIKE), AND THE SID. WE TALKED ABOUT THE REASONS FOR THE ENG-OUT/RADIO-OUT PART OF WHICH IS THE TERRAIN, BUT ALSO BECAUSE OF THE RESTR AREAS DESIGNED TO KEEP YOU FROM FLYING INTO THE NO-MAN'S-LAND/FREE FIRE ZONE A FEW MI N. THE WX WAS GOOD/CLR, WITH NOT MUCH WIND. ON THE RWY, THE CAPT GAVE ME THE AIRPLANE, AND WE GOT CLRNC FOR TKOF. NORMAL TKOF TILL ABOUT 500 FT, WHERE I ANNOUNCED THAT I WAS STARTING MY L TURN. I DON'T KNOW IF THE L TURN WAS CAUGHT BY THE CAPT. SINCE THE WX WAS CLR, WE WERE BOTH LOOKING OUT, NOT ONLY FOR TFC, BUT FOR THE LANDMARKS CONCERNING THE RESTR AREA (FREE FIRE ZONES), AND THE TERRAIN, WHICH REQUIRED THE ENG-OUT/LOST COMS PROCS. UNFORTUNATELY, THE SID DID NOT REQUIRE A L TURN AT THAT POINT. THE CAPT CAUGHT THE ERROR AFTER I WAS ESTABLISHED IN THE TURN, ABOUT THE SAME TIME AS I DID. WE WERE IN A TURN BACK TO THE R, WHEN DEP CTL REQUESTED OUR HDG, AND GAVE US A TURN TO 220 DEGS. THERE WAS NO OTHER TFC ON TKOF OR ON APCH TO EITHER RWY, WHOM WE MIGHT HAVE INTERFERED WITH. AFTER ESTABLISHED IN THE CLB AND ON HDGS, DEP ASKED WHY WE DEVIATED. THE CAPT SAID THAT THERE WAS AN ERROR IN USING THE FMC, NOT SURE THE EXACT WORDS. I WAS KIND OF IN SHOCK AT WHAT JUST OCCURRED! DEP ASKED IF THERE WERE ANY FURTHER PROBS, AND THE CAPT ASSURED HIM THAT THERE WERE NONE. THERE WAS NO FURTHER DISCUSSION ON THE DEV WITH ATC. I APOLOGIZED FOR THE ERROR AND CONFESSED I HAD NO CLUE AS TO WHY. LATER THE CAPT SAID HE WOULD FILL OUT A RPT. I MADE THE ASSUMPTION (FALSE!) THAT IT WAS FOR BOTH OF US. I DON'T KNOW WHY I MADE THE TURN EARLY, CONSIDERABLY EARLY. IT MIGHT HAVE BEEN SOMETHING TO DO WITH THE RESTR AREAS. THERE IS NOTHING THAT I AM CONSCIOUSLY AWARE OF. BELIEVE ME, I HAVE SEARCHED. I KNOW THAT IN FLYING TAG LEGS FOR OVER A YR, I STILL DON'T GET GOOD REST THE NIGHT BEFORE THIS LEG. THIS NIGHT WAS NO BETTER. GOT A COUPLE OF HRS OF INCOMPLETE SLEEP, THOUGH I WAS IN BED FOR 8 HRS WITH LIGHTS OUT. THE TIME OF TKOF IS USUALLY (HOME/BODY TIME) ABOUT 2 HRS BEFORE MY REGULAR GO-TO-BED/SLEEP ROUTINE. HOWEVER, I DON'T RECALL BEING SLEEP DEPRIVED AT THIS TIME. ALSO, THOUGHT ABOUT THE IMPACT OF OUR COMPANY PROBS. I HAVE TRIED TO NOT LET THEM INTERFERE WITH MY PERFORMANCE. THERE IS ALMOST NO INFLUENCE ANY OF US HAVE ON THE ULTIMATE (AND UNKNOWN) OUTCOME. I CAN'T PUT MY FINGER ON ANYTHING LIKE THAT. BUT, I CAN'T GUARANTEE THERE IS NO IMPACT.

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.