UNAUTH LNDG. CLRNC LNDG NOT RECEIVED.

Narrative

THE LEARJET I WAS FLYING WAS CLRED FOR A VISUAL APCH AT ORD RWY 27L WITH A SPD OF 170 KTS TO MARKER. I MADE THE TURN TO FINAL AT 5000 FT AND 170 KTS. THERE WERE OTHER ACFT AHEAD AND TO THE R MAKING VISUAL APCHS TO RWY 27R; AND WE WERE FOLLOWING A LARGE ACFT. I STAYED ON THE LOC AND ABOVE GS SO AS NOT TO ENCOUNTER ANY WAKE TURB. APCH CTL WAS VERY BUSY AND THE COPLT WAS WATCHING THE ACFT TO OUR R. AS WE WENT BY THE MARKER WE COMPLETED THE LNDG CHKLIST AND I WAS TRYING TO STAY ABOVE GS AND JUDGE WHERE THE OTHER ACFT WOULD TOUCH DOWN; SO AS TO MAKE A SAFE APCH AND LNDG. AT ABOUT 50 FT JUST BEFORE TOUCHDOWN; I REALIZED THAT I WAS STILL LISTENING TO THE APCH CTLR AND NOT THE TWR. THE OTHER ACFT HAD CLRED THE RWY; AND I WAS NOT GIVEN ANY VISUAL SIGNAL FROM THE TWR; SO I ELECTED TO LAND. I TURNED OFF AT THE FIRST HIGH SPD AND HELD SHORT OF TXWY M. THE COPLT WENT TO THE TWR FREQ AND WAS TOLD TO GAR. FAILURE TO SWITCH TO TWR FREQ AS PER APCH CTL'S INSTRUCTIONS (ADMITTED). CAPT MISSING RADIO CALL; COPLT INEXPERIENCE AND FIXATION ON TFC AND DISTRS IN THE COCKPIT.