PIPER PA31 PLT DSNDED BELOW AN APCH FIX DURING A VOR APCH RESULTING IN APCH CTLR INTERVENING AND ADVISING THEM OF THEIR LOW ALT.

Narrative

AFTER A LONG NIGHT OF WAITING ON A CHARTER FLT; I WAS ASKED TO FLY A TRIP FOR A CUSTOMER. I ASKED ANOTHER PLT TO RIDE ALONG TO HELP WATCH ME AND HELP WITH THE WORKLOAD. WE FLEW INTO ATL AND WE ALSO FLEW THE VOR APCH INTO DNL. WE TALKED ABOUT THE APCH AND STEPDOWNS; MINIMUM ALT; MISSED APCH; ETC. WE CROSSED THE VOR AT 3000 FT AND I DSNDED TO 2100 FT; AND AT 5 NM FROM THE VOR I STARTED DOWN TO 1060 FT; THE NEXT STEPDOWN ON THE APCH. I HAD LOOKED AT THE PLAIN VIEW ON THE CHART AND MISTOOK THE 5 NM FIX FOR THE NEXT STEPDOWN; THE 10 NM FIX ACTUALLY IS THE NEXT STEPDOWN. AT ABOUT 9 NM FROM THE VOR; AUGUSTA APCH CALLED AND TOLD US WE WERE SHOWING 1100 FT AND HAD NOT GOTTEN TO THE 10 NM FIX YET AND SHOULD BE AT 2100 FT. WE WERE IN MVFR CONDITION DUE TO HAZE. I LOOKED AT THE OTHER PLT AND HE LOOKED AT ME AND I ASKED 'WHERE DID I SCREW UP?' I DID NOT HAVE AN APCH PLATE ON MY YOKE OR LAP LIKE I NORMALLY DO. CORRECTIONS TO BE MADE: 1) HAVE THE APCH PLATE IN PLAIN VIEW OF ME. 2) REFUSE TRIPS IF I HAVEN'T HAD THE PROPER REST. OTHER PLTS NOT THE ANSWER (SOMETIMES HARD TO DO -- COMPANY PRESSURE). 3) CHALLENGE AND CONFIRM STEPDOWNS; DISTANCES. THIS MISTAKE WOULD BE DEADLY IN MOUNTAINS! 4) WITH THE HIGHER CEILINGS; I WAS THINKING 'THIS WILL BE AN EASY APCH!' GOES TO PROVE ALWAYS FLY THE APCH!