ACR LNDG WITHOUT CLRNC. UNAUTHORIZED LNDG.

Narrative

UNKNOWN TO US MEM TRACON WAS HAVING A PROBLEM WITH THEIR RADIOS. WE WERE ON A VISUAL APCH TO RWY 27 AT MEM WITH ABOUT A 5 KT TAILWIND. THE COPLT WAS FLYING. HE WAS SOMEWHAT INEXPERIENCED AND TENDED TO LET THE ACFT GET AHEAD OF HIM SO I CONCENTRATED ON HIS FLYING TO MAKE SURE THAT HE DIDN'T GET TOO FAR BEHIND AND DIDN'T NOTICE THAT APCH HAD NOT CHANGED US OVER TO TWR. CONSEQUENTLY WE LANDED WITHOUT CLRNC. WHEN WE DID CONTACT MEM TWR ON THE GND THEY TOLD US ABOUT THE RADIO PROBLEM. THERE WAS NO PROBLEMS LNDG WITHOUT CLRNC. SUPPLEMENTAL INFO FROM ACN 202086. MEM APCH WAS VECTORING US TO A RWY 36R VISUAL APCH. AT APPROX 20 NM NE OF ARPT; THEY ASKED US IF WE WOULD LIKE THE VISUAL TO RWY 27. WE ACCEPTED AND IMMEDIATELY STARTED TO CONFIGURE BECAUSE WE WERE HIGH. DURING THE APCH I MENTIONED TO THE CAPT THAT WE HAD A 'PRETTY GOOD TAILWIND' HE CONCURRED AND WE PRETTY MUCH CONCENTRATED ON GETTING THE ACFT DOWN ON THE GS AND 'ON- SPD.' AFTER ROLLOUT AND TURNING ACFT OVER TO CAPT I (CO- PLT) STARTED TO SWITCH TO GND AFTER THE TURNOFF AND NOTICED WE WERE STILL ON APCH CTL. AFTER CONTACTING GND; THEY SAID; 'THEY'RE HAVING SOME TROUBLE DOWN THERE;' WE ASSUMED THAT MEANT APCH CTL AND FOR WHATEVER REASON THEY NEVER SWITCHED US OVER TO TWR. WE WERE AFRAID WE HAD LANDED WITHOUT LNDG CLRNC; AND ASKED GND IF 'THAT WAS A PROBLEM.' THEY SAID 'NO PROBLEM.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR GAVE TIME IN TYPE AND ALSO EXPERIENCE LEVEL OF FO. WHILE ON FINAL THEY HEARD A SMT TRYING TO CALL APCH CTL WITHOUT ANY ANSWER; BUT DID NOT REALIZE THAT TRACON HAD RADIO PROBLEM UNTIL TWR TOLD THEM AFTER LNDG.