A B767 CREW EXPERIENCES A MAP SHIFT WHILE ATTEMPTING TO ALIGN WITH THE RWY 25R ILS LOC. ACFT HAD BEEN ON THE APCH FOR RWY 24R AND HAD BEEN SHIFTED OVER TO THE S COMPLEX BY APCH CTLR.

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THE REMARKS SECTION OF OUR FLT PLAN CONTAINED A WARNING TO WATCH FOR AN FMS MAP SHIFT INBOUND TO LAX. IT SAID SEVERAL ACFT HAD EXPERIENCED MAP SHIFTS DURING THE ARR. WE WERE CLRED DIRECT 'CIVET' INTXN AND WERE EXPECTING THE 'CIVET' ARR TO RWY 25L. THE FMS WAS PROGRAMMED FOR A 'CIVET' ARR AND ILS RWY 25L. ATC THEN CHANGED OUR CLRNC TO THE 'MITTS' ARR; DIRECT 'SNRKL' INTXN; CROSS 'SNRKL' AT OR ABOVE 12000 FT; CLRED ILS RWY 24R. WE RETUNED THE NAVAIDS AND REPROGRAMMED THE FMS FOR A 'MITTS' ARR TO RWY 24R. WE WERE ISSUED TFC TO OUR L SEVERAL TIMES BUT NEVER DID SEE THE TFC. ATC THEN OFFERED; AND WE ACCEPTED RWY 25R. I TUNED THE LOC AND WENT TO A RAW DATA DISPLAY ON MY HSI; WHILE THE CAPT LOOKED FOR THE RWY 25R APCH PLATE AND THEN SELECTED THE ILS RWY 25R IN THE FMS. WE WERE INSTRUCTED TO JOIN THE RWY 25R LOC; CROSS 'MUSIK' INTXN AT OR ABOVE 8000 FT; CLRED ILS RWY 25R. I DON'T RECALL SEEING OUR POS IN RELATION TO THE RAW DATA DISPLAY OF THE LOC BECAUSE I WAS DISTRACTED AT THIS POINT: THE ACFT MADE AN ABRUPT L TURN; AND THEN WE GOT A TCASII RA TO 'REDUCE DSCNT.' I BELIEVE THE ABRUPT L TURN WAS CAUSED BY A MAP SHIFT THAT BECAME APPARENT A BIT LATER. ANYWAY; WE RESPONDED TO THE TCASII WARNING. THEN I SAW THE ARPT VISUALLY AND REALIZED WE WERE WELL S OF THE LOC WHEN I EXPECTED TO BE N OF THE LOC. WE INITIATED A R TURN BACK TOWARD THE LOC IMMEDIATELY; AND INFORMED ATC THAT WE WERE CORRECTING. AT THIS POINT I COULD SEE THAT THE CAPT'S DISPLAY SHOWED US ABOUT 5 MI N OF THE LOC; WHEN IN REALITY WE WERE S OF THE LOC. THE ARR AND RWY CHANGES MADE DETECTING THE MAP SHIFT ALMOST IMPOSSIBLE UNTIL IT WAS TOO LATE. I THINK THE PNF SHOULD MONITOR RAW DATA AT ALL TIMES DURING ARRS TO LAX ARPT. SUPPLEMENTAL INFO FROM ACN 396417: MOMENTS PASSED AS WE SET UP FOR THAT CLRNC. ATC CONTINUED TO CALL WITH TFC; AIRSPD RESTRS; AND FREQ CHANGES; REQUIRING RESPONSES AND INTERRUPTIONS TO OUR FMS SET-UP. WE WERE GIVEN ANOTHER FREQ CHANGE. SOCAL APCH CTL IMMEDIATELY OFFERED US RWY 25R. ALTHOUGH ALMOSTREFUSING THE OFFER; IT WAS ACCEPTED FOR THE SHORTER TAXI TIME TO THE GATE. (ALMOST REFUSED DUE TO MULTIPLE CLRNC CHANGES ALREADY AND DIFFICULTY; DUE TO TIME CONSTRAINTS AND UNFAMILIARITY; IN NEW SETUPS FOR EACH CHANGE AND MULTIPLE CALLS FROM ATC INHIBITING OUR CLRNC PROCESSING.) SOCAL APCH THEN CLRED US TO INTERCEPT THE RWY 25R LOC. LOOKING AT MY HSI MAP; I EXPECTED TO HAVE TO TURN L SLIGHTLY TO INTERCEPT THE LOC. THE AUTOPLT ALREADY WAS/HAD BEEN IN A LOW-BANK TURN TO THE L. THIS PUZZLED ME FOR A MOMENT. THE INTERCEPT ANGLE WAS ALREADY TOO GREAT SO I INTERCEDED AND REDUCED THE ANGLE. SOCAL APCH HAD CLRED US FOR THE APCH. ALMOST IMMEDIATELY OUT OF 8000 FT; WE HAD A TCASII ALERT; 'REDUCE DSCNT.' WHEN I LOOKED AT THE TCASII; THE ALERT SOUNDED ONE MORE TIME AS I SAW A TARGET PASS 500 FT; MORE OR LESS UNDER US; ALSO IN A DSCNT. AT THAT TIME A PLT JUMP SEAT RIDER BEHIND ME POINTED OUT BY VISUAL REF TO THE ARPT THAT WE WERE S OF BOTH RWY 25L AND RWY 25R LOCS AND GOING FURTHER S. I IMMEDIATELY WENT TO RAW DATA; MADE A CORRECTION BACK TO THE R TO INTERCEPT RWY 25R LOC AND FURTHER REDUCED OUR RATE OF DSCNT. AUTOPLT LOC WAS ALSO ARMED. WITHIN SECONDS; WE WERE ON THE LOC AND THE REMAINDER OF THE FLT PROGRESSED NORMALLY. NEEDLESS TO SAY; WE SPENT SOME TIME ANALYZING THIS. OUR FIRST REALIZATION WAS THAT WE'D EXPERIENCED A 'MAP SHIFT;' WITHOUT RECOGNIZING IT IMMEDIATELY. UPON REALIZING THAT WE WERE CHASING A PHANTOM LOC TO THE S (L); WE RECOGNIZED THE SHIFT. MINS LATER; AT THE GATE; MAINT CONFIRMED A SHIFT OF AT LEAST 2 1/2 MI. ON REFLECTION; WE MIGHT HAVE SAVED SOME OF THIS IRREGULAR OP HAD WE: 1) ARMED THE AUTOPLT FOR LOC INTERCEPTION IMMEDIATELY AFTER RECEIVING THE CLRNC AND DIALING IN THE LOC FREQ. 2) DOWNLOADED SOME OF THE AUTOMATION RIGHT AWAY AND GONE TO MANUAL AND RAW DATA MODE. 3) REFUSED THE OFFER OF RWY 25R SINCE WE WERE SET UP FOR RWY 24R. NORMALLY; WE DON'T INTERCEPT THE LOC TOO FAR OUT BECAUSE IT'S TOO UNSTABLE AND CAUSES THE ACFT TO WING WALK TOO MUCH. INSTEAD; WE USE THE FMS CALCULATED LOC; AND ARM THE LOC WHEN IN CLOSER. STANDARD PROC ALSO CALLS FOR 1 PLT TO BE ON RAW DATA FOR LOC INTERCEPT. THAT WAS DONE; BUT WE WERE PLAYING CATCH-UP WITH THE CLRNC AND FAILED TO CATCH THE RAW DATA DISCREPANCY RIGHT AWAY. ALL OF THIS HAPPENED IN A VERY SHORT TIME FRAME; COMPRESSED AND COMPLICATED BY AN UNUSUALLY HIGH NUMBER OF CALLS FROM ATC. ALTHOUGH RAW DATA WAS AVAILABLE TO CORRECT US; WE DID NOT SEE IT IN THE FEW SECONDS AVAILABLE BEFORE WE REALIZED IT ANYWAY. THE MAP SHIFT WAS A SERIOUS COMPLICATION. IT HAD ALREADY POINTED THE ACFT TOWARDS THE SW BEFORE WE SAW IT. WITHOUT ALL THE CLRNC CHANGES; THE MAP SHIFT MORE THAN LIKELY WOULD HAVE BEEN CAUGHT MUCH MORE QUICKLY; IF NOT IMMEDIATELY. WITH PAST KNOWN MAP SHIFTS; I WOULD RECOMMEND THAT 1 PLT MONITOR THE ENTIRE ARR AND APCH; AS WE DO IN MEXICO CITY. NEVER LET ATC FURTHER COMPLICATE OR RUSH YOUR ARR/APCH. AND DOWNLOAD TO THE APPROPRIATE LEVEL OF AUTOMATION IMMEDIATELY WHEN NECESSARY. WITH MY 11 YRS EXPERIENCE IN GLASS COCKPITS; I REALLY THOUGHT THAT I WAS MORE IMMUNE TO THIS KIND OF THING HAPPENING TO ME THAN MOST. LET ME TELL YOU. CIRCUMSTANCES CAN CONSPIRE TO TRAP ANY UNSUSPECTING VICTIM.