A B727 FLC WAS CLRED FOR AN APCH THAT THEY LEGALLY COULD NOT FLY WITHOUT ATC RADAR ASSISTANCE. THE FLC REQUESTED THE ASSISTANCE; BUT DID NOT RECEIVE IT FROM ATC.

Narrative

WE WERE BEING VECTORED FOR THE LOC RWY 27L APCH AT CHICAGO O'HARE ARPT. THE GS WAS RPTED OTS ON THE ATIS. ALTHOUGH THIS IS NOT DESIGNATED A LOC AND DME APCH ON THE COMMERCIALLY PUBLISHED IAP CHART; LOC DME WAS NEEDED TO IDENT THE STEP-DOWN FIXES; EXCEPT FOR THE OM. SEVERAL ACFT AHEAD RPTED THE DME OTS. ATC ACKNOWLEDGED THIS; BUT CONTINUED TO CLR ACFT FOR THE APCH; AS THOUGH OBLIVIOUS TO THE FACT THAT DME WAS NECESSARY TO DSND FOR LNDG. THE SAME CONDITION EXISTED FOR OUR APCH. ATC WAS SO OVERLOADED THEY COULD NOT RECEIVE OUR ADVISORY THAT THE DME WAS OUT OR OUR REQUEST TO CALL THE INITIAL STEP-DOWN FIX. FORTUNATELY THERE WAS A BREAK IN THE CEILING AND WE WERE ABLE TO DSND VISUALLY AND CLR OF THE CLOUDS. THIS APPEARS TO BE A SIT WHERE A CTLR WHO IS VERY COMPETENT AT CTLING PLANES IS UNFAMILIAR WITH OUR END OF THE EQUATION AND CANNOT MEET OUR NEEDS. THE CTLR WAS ALSO OVERLOADED; AND THEREFORE A BREAKDOWN IN COM TOOK PLACE SO THAT IMPORTANCE OF THE DME REQUIREMENT NEVER REGISTERED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR BELIEVES THAT THIS PROB WAS EXACERBATED BY A COMS GAP. ATC MAY NOT HAVE TAKEN ANY ACTION TO CHANGE THE SIT BECAUSE THEY ARE EITHER UNAWARE OF THE PARTICULAR NEEDS ASSOCIATED WITH EACH TYPE OF ACFT EQUIP OR THEY ARE GETTING USED TO THE NEWER GENERATION ACFT WITH INTERNAL NAV SUCH AS ACFT WITH FMC SYS. EVERYONE ON THE APCH WAS MANAGING IN SOME WAY OR ANOTHER; WHETHER IT WAS THROUGH USE OF AN FMC OR BY UTILIZING THE DME OFF THE VOR FOR A GENERAL FIX; AS THIS FLC MANAGED. THE VISUAL CONDITIONS BELOW A 2500 FT OVCST (ACTUALLY APPEARED BROKEN) ALLOWED THE FLC TO VISUALLY DSND TO THE RWY FOLLOWING THE LOC. RPTR SUGGESTS THAT THE CTLR SHOULD HAVE AT LEAST BEEN STATING; 'INTERCEPT THE LOC; I'LL CALL THE FIXES FOR YOU.'