SF340 CREW DSNDS BELOW CHARTED ALT ON APCH IN CZYZ AIRSPACE.

Narrative

WE WERE DSNDING FROM CRUISE ALT TO LAND AT THE CIU ARPT; APCHING THE ARPT FROM THE SE. WE WERE EXPECTING TO GET A VISUAL APCH TO RWY 33; AND WERE ANTICIPATING THE CTLR TO GIVE US A LOWER ALT THAN THE ASSIGNED 4000 FT MSL (WHICH WE WERE FLYING AT). AT 4000 FT WE WERE JUST IN THE BASES OF THE OVCST LAYER AND HAD INTERMITTENT GND CONTACT BELOW. THIS IS THE FIRST TIME BOTH MYSELF OR THE COPLT HAD BEEN TO THE CIU ARPT. WE ASKED THE CTLR FOR LOWER; AS WE WANTED TO BREAK OUT AND GO VISUALLY. WHEN HE ADVISED US THAT THIS ALT WAS AS LOW AS HE COULD GIVE US; WE WERE ABOUT 15 MI FROM THE ARPT. I REALIZED WE WOULDN'T GET IN VISUALLY SO I ASKED FOR A VECTOR TO THE NDB APCH TO THE LNDG RWY. WE WERE PRACTICALLY ON THE INBOUND COURSE ANYWAY. WE WERE RUSHED AND DIDN'T LOOK AT THE APCH PLATE CLOSE ENOUGH. THERE IS A STEPDOWN FIX ON THE APCH AT AROUND 30 DME FIX FROM ANOTHER VOR'S XING RADIAL. AT THIS POINT WE COULD DSND TO 2400 FT TO VFR CONDITIONS; WHICH IS WHAT WE WANTED TO DO. (JUST USE THE APCH TO GET BELOW THE BASES AND GO VISUALLY.) WHEN WE TUNED IN THE XING VOR'S RADIAL AND DME TO DETERMINE OUR STEPDOWN FIX; IT READ 28.5 DME. WE PROCEEDED DOWN TO 2400 FT; AS WE WERE ON THE INBOUND COURSE ESTABLISHED AND BELIEVED WE HAD CROSSED THE STEPDOWN FIX. WE BROKE OUT VISUALLY AND HAD THE FIELD IN SIGHT. THE CTLR TOLD US TO CLB BACK TO 4000 FT AS WE HAD DSNDED TOO EARLY. WE CLBED BACK INTO THE CLOUDS AND FIGURED OUT THAT INSTEAD OF THE DME NORMALLY COUNTING DOWN AS WE EXPECTED; IT SHOULD HAVE GONE UP BASED ON THE ANGLE OF THE XING RADIAL. AT 28.5 DME; WE WERE ACTUALLY 1.5 MI AWAY FROM THE STEPDOWN. INSTEAD WE THOUGHT WE WERE 1.5 MI INSIDE (PAST) THE FIX. SOME FACTORS THAT LED US INTO THIS SIT WERE THAT WE WERE EXPECTING A VISUAL APCH INITIALLY AND HADN'T EXPECTED TO USE THE APCH UNTIL WE WERE VERY CLOSE TO THE ARPT. THIS LED US TO RUSH THE APCH BRIEF AND NOT CAREFULLY REVIEW THE APCH PLATE AS WE WOULD NORMALLY DO. THIS COULD HAVE BEEN A DEADLY MISTAKE IN MOUNTAINOUS TERRAIN. NEXT TIME I WILL TRY TO ESTABLISH FROM THE CTLR WHAT APCH TO EXPECT FURTHER OUT FROM ARPTS. IF THE WX IS MARGINAL; I WILL ASK FOR THE APCH FURTHER OUT AND HAVE MORE TIME TO SET UP AND BRIEF THE APCH.