FMC DROPPED INITIAL INTXNS BTWN DEN AND DVC PROMPTING CREW TO PROCEED DIRECT TO DVC RATHER THAN THE PRELIMINARY ROUTING PRIOR TO DVC.
Synopsis
FMC DROPPED INITIAL INTXNS BTWN DEN AND DVC PROMPTING CREW TO PROCEED DIRECT TO DVC RATHER THAN THE PRELIMINARY ROUTING PRIOR TO DVC.
Narrative
ON ACR FLT XXX; DEC/XA/95; WE PROGRAMMED OUR FMC WITH THE DENSAN RTE; WHICH WAS IN THE DATABASE. WE SELECTED THE ROCKI 2 DEP AND THE DVC TRANSITION; THE RWY; AND ACTIVATED THE RTE AFTER CHKING THAT EVERYTHING WAS IN. AFTER TKOF AND CLBING OUT SW IN VFR CONDITIONS; WE EXPERIENCED A DELAY IN RECEIVING AN ALT CLRNC ABOVE 10000 FT. AFTER THAT WE WERE CLRED ON A HEADING TO INTERCEPT THE DVC TRANSITION. WE ACTIVATED AN INTERCEPT TO THE FIRST WAYPOINT ON THE LEGS PAGE. A SHORT TIME LATER ZDV CALLED AND SAID THAT WE WERE S OF THE DVC TRANSITION. WE CHKED AND FOUND THAT THE WAYPOINT THAT WE USED TO ACTIVATE THE LEG WAS THE DVC VOR AND NOT BAYLR INTXN. THE RTE PAGE INDICATED THAT ROCKI 2 WITH DVC TRANSITION WAS PART OF THE ACTIVE RTE. HOWEVER; THE INTERMEDIATE WAYPOINTS WERE NOT ON THE ACTIVE LEGS PAGE WHEN WE WENT TO ACTIVATE THE TRANSITION TO FLY ON LNAV. I SHOULD HAVE CHKED CLOSER WHEN I CALLED FOR THE INTERCEPT TO THE FIRST WAYPOINT. WE WERE S OF COURSE BUT I DO NOT FEEL THAT ANY TFC CONFLICT OCCURRED. SUPPLEMENTAL INFO FROM ACN 323462: NAV ERROR OCCURRED DURING CLBOUT FROM DEN. CLRNC WAS DEN ROCKIES 2 DOVE CREEK TRANSITION. WE TOOK OFF RWY 25; CLBED TO 10000 FT HEADING 240 DEGS. DEP WAS WORKING ARRS OVER US AND DID NOT CLR US TO CLB UNTIL WE ASKED FOR HIGHER ALT 20 PLUS MI SW OF DEN. SWITCHED TO CTR FREQ CLR TO FLY HEADING 230 DEGS INTERCEPT ROCKIES 2 DVC TRANSITION. I WENT TO CDU AND EXTENDED DVC WHICH WAS THE FIRST FIX SHOWING. SOMEHOW THE FMC HAD DROPPED BAYLR AND BOBBA INTXNS. RTE INTO DVC WAS NOT THE DEP TRANSITION BUT SOME DISTANCE S. A 230 DEG HDG WAS PARALLEL TRACK TO THE RTE SHOWING BUT S OF THE CORRECT COURSE. I BECAME SUSPICIOUS THAT THE RTE WAS NOT CORRECT. WHEN THE ASSIGNED 230 DEG HDG WOULD NOT INTERCEPT BEFORE DVC VOR. I SWITCHED TO MANUAL VOR (RAW DATA) AND SAW WE WERE S OF COURSE AT WHICH TIME ATC CALLED AND ASKED IF WE WERE ON COURSE. I ESTIMATE WE WERE 3-5 MI S OF DESIRED COURSE. I BELIEVE THIS HAPPENED AS A RESULT OF NOT DOUBLE-CHKING THE LEGS PAGE OF THE FMC AND BEING DISTRACTED BY THE LACK OF A CLB CLRNC ABOVE 10000 FT SW OF DEN. I HAVE STARTED TO TRUST THE FMC TOO MUCH AND HAVE STOPPED BACKING IT UP WITH RAW DATA.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.