AN ATX LTT FLC MISREFS A XING POINT DURING A STAR TO SNA. THEY WERE TOO HIGH AT MERMA. NO CONFLICT.

Narrative

CLRNC: CLRED FOR THE TANDY 3 ARR TO SNA VIA THE FELLOWS VOR (FLW) AND CROSS MERMA AT 14000 FT. THE PF (SIC) PROGRAMMED THE VERT NAV UNIT TO PROVIDE A DSCNT PROFILE SO AS TO MEET THE XING RESTR. I FAILED TO VERIFY THAT THE INPUTS WERE CORRECT. ABOUT 4 MINS PRIOR TO INTXN AND WHILE DSNDING FROM FL260; I BEGAN TO REVIEW THE ILS APCH AT OUR DEST. UPON DOING THIS; I CONTACTED THE ARPT FBO ON OUR OTHER VHF TRANSCEIVER TO ALERT THEM OF OUR ETA. THE SIC (PF) CONTINUED TO MONITOR ATC. I WAS DISTR AND WAS NOT PAYING ATTN TO OUR PROGRESS. ABOUT 3 MI PRIOR TO MERMA; I HAD COMPLETED MY TASKS AND RETURNED TO MONITOR ATC COM. WE WERE NOW DSNDING THROUGH FL200. IT WAS AT THIS POINT THE CTLR ASKED 'N-NUMBER; ARE YOU GOING TO MAKE MERMA AT 14000 FT?' 'NEGATIVE' WAS MY RESPONSE. THE SIC DEPLOYED THE AIR BRAKES AND BEGAN A RAPID DSCNT. WE LEVELED AT 14000 FT; 7 MI PAST MERMA. THERE WERE NO APPARENT TFC CONFLICTS. THE REMAINDER OF THE FLT WAS ROUTINE AND UNEVENTFUL. UPON LNDG WE DISCUSSED THE EVENT. IT TURNED OUT THAT THE PF HAD NOT PROGRAMMED THE VERT NAV GUIDANCE UNIT PROPERLY. THIS PARTICULAR ARR PROC BEGINS AT EITHER THE FILMORE VORTAC (FIM) OR THE FELLOWS VORTAC (FLW). WE HAD BEEN CLRED VIA THE FLW TRANSITION. MERMA IS 112 MI PAST FLW. THE PF; WHO INCIDENTALLY HAS DEMONSTRATED OVER THE LAST 6 MONTHS (SINCE HIS EMPLOYMENT) TO BE A PARTICULARLY COMPETENT PLT WITH A GOOD EYE FOR DETAIL; INADVERTENTLY PROGRAMMED THE VERT NAV UNIT TO CROSS MERMA BASED ON ITS DISTANCE FROM FIM. THIS ERROR WENT UNNOTICED BY BOTH OF US UNTIL IT WAS TOO LATE. PERHAPS THE FACT THAT FELLOWS AND FILMORE SOUND ALIKE AND ARE VERY NEAR TO EACH OTHER CAUSED A SUBCONSCIOUS MISTAKEN IDENT OF THE PROPER VOR. MODERN ELECTRONIC NAV COMPUTERS ARE NICE; HOWEVER; THEY ARE ONLY AS GOOD AS THE DATA THAT'S INPUT. VERIFYING INPUTS AND USING BASIC RULES OF THUMB TO CHK REASONABLENESS OF GUIDANCE INFO ARE STILL NECESSARY. THIS; ALONG WITH DISTR AND COMPLACENCY ON MY PART; CONTRIBUTED TO THIS ERROR.