A LIGHT ACFT'S FLC FAILED TO CONTACT THE TWR; AND LANDED WITHOUT A CLRNC TO LAND.

Narrative

I WAS THE PF IN TURB CONDITIONS EVEN THOUGH VMC EXISTED I WAS CONCENTRATING ON THE GAUGES. MY COPLT WAS TALKING TO GREENSBORO APCH AT APPROX 500 FT AGL I INQUIRED TO MY COPLT THAT I HAD NOT HEARD ATC CLR US TO LAND. THE COPLT INFORMED ME THAT HE WAS NOT TALKING TO THE TWR YET BECAUSE APCH HAD NOT HANDED HIM OFF YET. I STATED THAT ANYTIME YOU ARE INSIDE THE OM ON APCH YOU SHOULD BE ON TWRS FREQ. THE COPLT PROCEEDED TO ARGUE WITH ME THAT MY STATEMENT WAS NOT TRUE IN ALL CASES. I THEN REQUESTED HIM TO ASK APCH IF HE WANTED US ON THE TWR FREQ. THE COPLT DID SO AND THE APCH CTLR ASKED OUR POS AND STATED THAT HE HAD LOST OUR XPONDER CODE ON RADAR AND THAT HE HAD FORGOTTEN TO SWITCH US OVER TO TWR. OUR POS AT THIS TIME IS 20 FT ABOVE RWY 23 JUST ABOUT STARTING TO FLARE FOR LNDG. MY COPLT SWITCHED TO TWR FREQ AND BEFORE THEY COULD CLR US TO LAND MY WHEELS TOUCHED THE PAVEMENT. AS WE TAXIED OFF THE RWY AND SWITCHED TO GND THE GND CTLR ADVISED US THAT WE LANDED WITHOUT CLRNC. AFTER TAXIING TO THE FBO; I CALLED THE TWR TO CLARIFY ANY MISUNDERSTANDING. THEY STATED EVERYTHING WAS OK AND DID NOT FIND FAULT WITH THE APCH CTLR (ATC SUPVR) OR WITH ME AND MY COPLT. THEY STATED THE HAZARDS OF LNDG WITHOUT A CLRNC. I TOLD THEM THAT I DEBATED ABOUT DOING A GAR BUT FELT SINCE THE RWY WAS CLR IT WOULD BE LESS CONFUSING TO LAND. THIS SIT COULD HAVE BEEN AVOIDED IF THE APCH CTLR HAD NOT FORGOTTEN TO SWITCH US TO TWR OR THAT MY COPLT; DUE TO LACK OF EXPERIENCE; WOULD HAVE QUERIED THE APCH CTLR ONCE WE PASSED THE OM TO FIND OUT IF HE WANTED US ON THE TWRS FREQ. I ALSO SHOULD HAVE BEEN MORE ATTENTIVE AND CAUGHT THE ERROR SOONER.