ATCT WAS NOT CONTACTED AND AN ACR FLC LANDED WITHOUT LNDG CLRNC.

Narrative

AT 7 MI FROM LNDG AT ATL RWY 27L; CAPT (PNF) SWITCHED TO COMPANY FREQ TO CHK ON OUR ARR GATE. I (PF) WAS BUSY FLYING A VISUAL APCH BEHIND A 757. CAPT CAME OFF COMPANY FREQ AT ABOUT 4 MI. WE COMPLETED LNDG CHKS AND LANDED. AFTER I GAVE CTL OF THE ACFT BACK TO HIM ON ROLLOUT; WE TURNED OFF AND I ASKED HIM IF WE WERE TO HOLD SHORT OF THE OTHER PARALLEL RWY (RWY 27R). IT WAS PRETTY OBVIOUS WE NEEDED TO BECAUSE THE 757 WAS HOLDING SHORT. WE BOTH LOOKED AT THE #1 COM AND REALIZED WE HAD LANDED ON APCH FREQ. WE SWITCHED TWR AND THE CTLR CONFIRMED HOLD SHORT OF RWY 27R. I READ THE NASA CALLBACK ISSUE DEALING WITH JUST THIS SIT; AND STILL DID IT! AFTER READING THAT ISSUE I HAD BEEN INCORPORATING THE SUGGESTED HABIT PATTERNS AS A PNF; BUT NOT AS THE PF. THE CAPT HAD BEEN CALLING COMPANY ON SHORT FINAL THE WHOLE TRIP AND I WAS UNEASY ABOUT HIM BEING OFF THE ATC FREQ THAT CLOSE TO LNDG AND SHOULD HAVE SAID SOMETHING ABOUT IT. HE ALSO WAS LAX ABOUT MAKING THE REQUIRED '1000 FT ABOVE MINIMUM/ARPT' CALL THAT PROMPTS ME TO CHK LNDG CLRNC. WE DEBRIEFED THE EVENT AND BOTH LEARNED FROM IT.