H25B FLT CREW RECEIVES LATE RWY CHANGE ON SEAVU STAR TO LAX. REPROGRAMMING OF FMS TO COMPLY RESULTS IN ALTDEV OVER DECOR INTXN.

Narrative

LOS ANGELES APCH CTL ASSIGNED FLT THE SEAVU.ONE ARR TO RWY 25R. WHEN FLT WAS APCHING CATAW; CREW RECEIVED AMENDED CLRNC: THE SEAVU.ONE ARR TO RWY 24R. I WAS CAPT/PIC SERVING ON THIS LEG AS THE PNF. I AM PROFICIENT WITH THE COLLINS PRO-LINE NAV SYS IN THIS ACFT. HOWEVER; I WAS EXTREMELY RUSHED TO GET THE ALTERED APCH LOADED INTO THE FMS. I OVERWROTE THE EXISTING ARR USING THE NEW RWY (WHICH REQUIRES DIFFERENT INTXNS). THE FMS SEEMED TO ACCEPT WHAT I HAD PROGRAMMED. THE AUTOPLT INDICATED IT WAS IN VERT NAV MODE AND HORIZ NAV MODE. HOWEVER; THE TURN TOWARD FINAL AND TOWARD DECOR INTXN WAS OVERSHOT. THE AUTOPLT WAS DISCONNECTED. AT THIS TIME; JUST OUTSIDE DECOR; THE CREW FIRST SAW PAST THE INITIAL DISTR OF BEING OFF COURSE TO NOTE THE ACFT WAS ABOVE ALT ASSIGNED AT DECOR; WHICH IS CHARTED 'BTWN 9800 AND 9000 FT.' THE ACFT PASSED OVER DECOR AT 10400 FT. FACTORS AFFECTING CREW: TOO RUSHED; UNFAMILIAR WITH LAX AND; THEREFORE; UNWILLING TO DECLINE AMENDED CLRNC. WE OUGHT TO HAVE ASKED TO BE 'TURNED OUT' TO CREATE TIME. OTHER FACTORS: CREW DEBRIEFING REVEALS WE BOTH FEEL THE FMS MALFUNCTIONED. SPECIFICALLY; INDICATING (AUTOPLT AND FLT DIRECTOR) ON COURSE AND DSCNT PATH. CDU'S SHOWED PROPER INTXNS AND ALTS; BUT ONBOARD INDICATIONS WERE ERRONEOUS.