FO OF A CARGO ACR B727 OVERSHOT THE DME ARC FOR A DME APCH RESULTING IN ARTCC RADAR CTLR INTERVENTION. THE FO IMMEDIATELY TURNED TO INTERCEPT THE PUBLISHED DME ARC AND MADE A SUCCESSFUL APCH AND LNDG.

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I ASKED CAPT WHAT ATC WOULD DO TO GET US OUR APCH AS TWR AND APCH CTL WERE CLOSED; AND THE ONLY OTHER TIME I WAS IN CPR THEY HAD BEEN OPEN. HE SAID; FROM EXPERIENCE; IT WOULD PROBABLY BE A HDG TO INTERCEPT THE DME ARC FOR A NON RADAR APCH. I ADVISED I HAD ONLY EVER EXECUTED A DME ARC ONCE; IN THE SIMULATOR; BUT WAS FAMILIAR WITH THE PROC. I BRIEFED THAT AT A PLANNED SPD OF 250 KTS ON INTERCEPT; I WOULD BEGIN THE TURN AT 32 DME TO INTERCEPT 29 DME ARC. THE CAPT CONCURRED; AND SHORTLY THEREAFTER ATC SAID THAT THE HDG WE WERE ON WOULD BE TO INTERCEPT THE 29 DME ARC. I DON'T REMEMBER EVER BEING 'CLRED' TO INTERCEPT THE ARC; ONLY TO EXPECT IT; THOUGH THE CLRNC MAY HAVE BEEN GIVEN AND I DID NOT 'HEAR IT' AS THE CAPT WAS WORKING THE RADIOS. I MAY HAVE BEEN DISTR AT THAT TIME; BUSY CALCULATING AND MONITORING OUR DSCNT WHICH WAS A SERIES OF STEPDOWNS IN MODERATE ICING WITH PWR ABOVE IDLE; SPD BRAKES DEPLOYED; OVER MOUNTAINOUS TERRAIN (BRAIN OVERLOAD). AT ABOUT 20 DME; ATC ASKED 'ARE YOU GOING TO TURN TO INTERCEPT THE ARC?' AT WHICH POINT I REALIZED I HAD MISSED THE TURN; AND IMMEDIATELY TURNED L TO INTERCEPT. ATC THEN CLRED US TO 13000 FT AND RECLRED(?) US FOR THE APCH; WHICH WAS 'UNEVENTFUL.' (IF A MOUNTAINOUS TERRAIN; MODERATE ICING; 500 AND 1; SNOW COVERED RWY APCH COULD BE CALLED THAT.)