FLC DOES NOT MAKE XING RESTR DSNDING INTO SLC.

Narrative

WHILE ON THE DSCNT TO SALT LAKE CITY (SLC) ON THE SPANE THREE ARR WE HAD TO DEVIATE TO THE N FOR BUILDUPS IN THE AREA. ZLC ASKED IF WE COULD PROCEED DIRECT TO FAIRFIELD VOR (FFU) AND CROSS 20 MI E AT 16000 FT. WE SAID YES. AS THE PNF; I ENTERED DIRECT FFU AND ASKED THE CAPT IF IT LOOKED GOOD; HE SAID YES AND ENTERED IT. WHILE TURNING TOWARDS FFU I ACCIDENTALLY ENTERED THE 16000 FT RESTR FOR THE VOR NOT FOR 20 DME E. APPROX 25 MI FROM FFU THE CAPT REALIZED WE WERE NOT GOING TO MAKE THE RESTR. I ASKED CTR 3 TIMES FOR RELIEF ON THE RESTR; BUT DUE TO RADIO CONGESTION I WAS NOT ABLE TO GET THROUGH UNTIL THE THIRD TIME. WE WERE GRANTED RELIEF ON THE ALT RESTR AND CROSSED THE 20 DME AT 18500 FT. WHY DID THIS HAPPEN? AN FMC IS ONLY AS GOOD AS THE PERSON WHO PROGRAMS IT. PROC IS TO HAVE THE OTHER PLT VERIFY THE ENTRY; THEN MONITOR PERFORMANCE OF THE VNAV. DUE TO THE LIMITED FMC EXPERIENCE I HAVE AND THE HIGH WORKLOAD ASSOCIATED WITH THE WX; TURB AND DSCNT I FAILED TO MAKE THE CORRECT ENTRY AND HAVE IT VERIFIED. OUR VERY HIGH WORKLOAD DOUBLED WHEN THE WRONG ENTRY WAS MADE. I WILL HAVE EVERY ENTRY VERIFIED IN THE FUTURE.