Narrative:

We missed the crossing restriction at bayst intersection on the profile descent into lax. In my opinion there several factors that contributed to the problem. Primary: overload of instructions by lax ATC in short time frame, and malfunction of VNAV. Secondary: time of day (dawn), 2-M crew, overemphasis on checklist which was done at correct time by company requirements but wrong time by workload, and captain's failure to stop checklist which had been initiated by first officer on his own. We were descending on the sadde 4 descent into lax approximately 4 mi from fim at approximately FL240 when we were reclred for a runway 24/25 profile descent. We were then told to disregard the restrictions at fim. I am not exactly sure of the exact sequence of events from this point, as things happened very quickly. We were told to keep the speed up, disregard the symon restrictions. Expect a stadium approach to 24R, contact approach on a different frequency, depart smo on a 70 degree heading. Add to this the descent and approach checklists. Somehow while programming the VNAV, the bayst restriction was dumped and was not caught by either myself or the first officer. We were cleared to 7000' at approximately bayst. We proceeded in and landed on 25R (yet another change). Nothing was said by approach re: bayst. I called approach by phone after our arrival and discussed the arrival and approach with the supervisor. He said there was no problem and that the controller thought he was helping to speed up our arrival into lax. I mentioned that we became overloaded and that we did not catch the restriction being dumped by our computers. On a subsequent leg into fll the VNAV malfunctioned again and was written up in the maintenance log book. Things happened so quickly on the arrival into lax that we were not sure of what happened to the VNAV descent. Going into fll we found the green arc and the descent page information inconsistent and incorrect. For example, the green arc showed up arriving at a restriction early while the page showed us 22 mi long. The aircraft just flew along and did its own thing. I have flown as captain on this aircraft 3.5 yrs and the first officer has 4 1/2 months on this equipment.

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Original NASA ASRS Text

Title: ACR HVT ALT DEVIATION UNDERSHOT ALT CROSSING RESTRICTION ON PROFILE DESCENT INTO LAX.

Narrative: WE MISSED THE XING RESTRICTION AT BAYST INTXN ON THE PROFILE DSNT INTO LAX. IN MY OPINION THERE SEVERAL FACTORS THAT CONTRIBUTED TO THE PROB. PRIMARY: OVERLOAD OF INSTRUCTIONS BY LAX ATC IN SHORT TIME FRAME, AND MALFUNCTION OF VNAV. SECONDARY: TIME OF DAY (DAWN), 2-M CREW, OVEREMPHASIS ON CHKLIST WHICH WAS DONE AT CORRECT TIME BY COMPANY REQUIREMENTS BUT WRONG TIME BY WORKLOAD, AND CAPT'S FAILURE TO STOP CHKLIST WHICH HAD BEEN INITIATED BY F/O ON HIS OWN. WE WERE DSNDING ON THE SADDE 4 DSNT INTO LAX APPROX 4 MI FROM FIM AT APPROX FL240 WHEN WE WERE RECLRED FOR A RWY 24/25 PROFILE DSNT. WE WERE THEN TOLD TO DISREGARD THE RESTRICTIONS AT FIM. I AM NOT EXACTLY SURE OF THE EXACT SEQUENCE OF EVENTS FROM THIS POINT, AS THINGS HAPPENED VERY QUICKLY. WE WERE TOLD TO KEEP THE SPD UP, DISREGARD THE SYMON RESTRICTIONS. EXPECT A STADIUM APCH TO 24R, CONTACT APCH ON A DIFFERENT FREQ, DEPART SMO ON A 70 DEG HDG. ADD TO THIS THE DSNT AND APCH CHKLISTS. SOMEHOW WHILE PROGRAMMING THE VNAV, THE BAYST RESTRICTION WAS DUMPED AND WAS NOT CAUGHT BY EITHER MYSELF OR THE F/O. WE WERE CLRED TO 7000' AT APPROX BAYST. WE PROCEEDED IN AND LANDED ON 25R (YET ANOTHER CHANGE). NOTHING WAS SAID BY APCH RE: BAYST. I CALLED APCH BY PHONE AFTER OUR ARR AND DISCUSSED THE ARR AND APCH WITH THE SUPVR. HE SAID THERE WAS NO PROB AND THAT THE CTLR THOUGHT HE WAS HELPING TO SPD UP OUR ARR INTO LAX. I MENTIONED THAT WE BECAME OVERLOADED AND THAT WE DID NOT CATCH THE RESTRICTION BEING DUMPED BY OUR COMPUTERS. ON A SUBSEQUENT LEG INTO FLL THE VNAV MALFUNCTIONED AGAIN AND WAS WRITTEN UP IN THE MAINT LOG BOOK. THINGS HAPPENED SO QUICKLY ON THE ARR INTO LAX THAT WE WERE NOT SURE OF WHAT HAPPENED TO THE VNAV DSNT. GOING INTO FLL WE FOUND THE GREEN ARC AND THE DSNT PAGE INFO INCONSISTENT AND INCORRECT. FOR EXAMPLE, THE GREEN ARC SHOWED UP ARRIVING AT A RESTRICTION EARLY WHILE THE PAGE SHOWED US 22 MI LONG. THE ACFT JUST FLEW ALONG AND DID ITS OWN THING. I HAVE FLOWN AS CAPT ON THIS ACFT 3.5 YRS AND THE F/O HAS 4 1/2 MONTHS ON THIS EQUIP.

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.