FLC STARTS AWAY FROM ASSIGNED RTE. FMS ANOMALY.

Narrative

OUR DEP CLRNC WAS THE LOOP 9 DAG TRANSITION EXPECT RWY 25R. TAXIING OUT OUR RWY WAS CHANGED TO RWY 24L. WHEN THE CO-PLT CHANGED THE RWY IN THE FMC FOR SOME REASON THE FMC ENTERED WAYPOINT FOR THE X-1 DEP. ON CLB WE WERE GIVEN DIRECT TO LAX AND ON COURSE. REACHING LAX THE FLT DIRECTOR CALLED FOR A TURN TO SLI AND I STARTED TO FOLLOW. HALF WAY THROUGH THE TURN I RECOGNIZED THE ERROR AND STARTED A TURN BACK. WE HAD ALMOST COMPLETED THE TURN WHEN ATC CALLED AND ASKED US WHERE WE WERE GOING. ONCE LEVEL AT CRUISE WE HAD OUR ORIGINAL RTE IN THE RTE 2 AND TRIED TO DUPLICATE THE PROB. TWICE THE FMC WOULD ADD THE WAYPOINTS FROM THE X-1 SID WHILE STILL SHOWING A LOOP 9 DEP IN THE RTE PAGE AND ON THE DEP AND ARR PAGE. I HAVE NEVER SEEN THIS COMING OUT OF LAX AND WONDER IF IT COULD NOT BE SOMETHING IN THE NEW DATABASE THAT CAME OUT ON JUN/THU/95. WE NEVER DEVIATED THAT FAR OFF COURSE BECAUSE; AS I SAID; I DID CATCH THE ERROR IN THE TURN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE WAS FLYING A 757-200. THE 'X-1 DEP' IS A COMPANY CUSTOMIZED CHART SPECIFICALLY FOR THE AIRLINE AND ITS DATABASE. LIKE HE SAID IN HIS RPT HE WAS ABLE TO GET THE FMS TO DEFAULT TO THE 'X-1 DEP' WITH THAT AIRPLANE; BUT THE COMPANY TRIED IN THEIR SIMULATOR AND IN OTHER AIRPLANES AND COULD NOT MAKE IT HAPPEN. THE LEGS PAGE SHOWED THE DISCREPANCY; AND ON TKOF THE FMS IS SELECTED TO THE LEGS PAGE FOR THE PNF AND TO THE PERFORMANCE PAGE FOR THE PF SO THAT ALL THE SPDS AND NUMBERS WOULD BE IN FRONT OF THE PF. THE LEGS PAGE OF COURSE WAS CHKED FOR ACCURACY PRIOR TO PUSHBACK; BUT CHANGING DEP RWYS WHILE TAXIING IS WHEN THE ERRONEOUS DEP SLIPPED IN. HE FIRST KNEW SOMETHING WAS WRONG WHEN THE AIRPLANE STARTED TURNING S AND AWAY FROM THE HOLLYWOOD BOWL.