A CL65RJ PIC'S RPT ON A POSSIBLE LOSS OF COM FREQ AND TFC SPACING WHILE LNDG AT STL.

Narrative

WE WERE CLRED FOR THE VISUAL APCH TO RWY 12R AT STL. WE CONTACTED THE TWR AND WERE CLRED TO LAND AS #3 WHEN WE WERE APPROX 15 NM FROM THE RWY; ON THE EXTENDED CTRLINE. WE HAD VISUAL CONTACT WITH TFC AHEAD AS IT LANDED AND CLRED THE RWY WHEN WE WERE ABOUT 3 MI OUT. JUST AFTER THAT; WE NOTED AN ACFT ROLLING FOR TKOF IN FRONT OF US. WE JUDGED THAT OUR ARR AFTER THE DEPARTING ACFT WOULD BE TIGHT; BUT WORKABLE; BASED ON OUR APPARENT RELATIVE SPDS AND DISTANCE. WE LANDED AFTER THE OTHER ACFT BECAME AIRBORNE AND QUICKLY CLRED THE RWY. NOT HEARING THE TWR SWITCH US TO GND CTL; WE SWITCHED ON OUR OWN AND WERE ISSUED TAXI INSTRUCTIONS TO OUR PARKING RAMP. WE WERE THEN TOLD TO PLEASE GIVE THE CTL TWR A CALL ON THE PHONE. WHEN I (THE CAPT) SPOKE TO THE PERSON AT THE NUMBER GIVEN; IT CAME TO LIGHT THAT THE TWR ISSUED AT LEAST 1 GAR CLRNC TO US. WE NEVER HEARD SUCH XMISSIONS AND I RELAYED THIS TO THE TWR MAN. WE SPECULATED IT MAY HAVE BEEN EQUIP RELATED; BUT CAME UP WITH NO LOGICAL CONCLUSIONS. I WAS ASKED THAT IN THE FUTURE; FACED WITH A SIMILAR SIT; THAT I VERIFY LNDG CLRNC AND MAYBE GO AROUND AT OUR OWN DISCRETION WHEN NO REPLY IS HEARD OR RECEIVED. END CONVERSATION. AT NO TIME DID WE RECEIVE SAID XMISSIONS AND RADIO TFC SEEMED NORMAL; BUSY. THIS KIND OF SPACING AND SEQUENCING IS NOT UNUSUAL IN OUR EXPERIENCE AT STL; SO WE DID NOT OVERLY QUESTION THE TIGHT SIT.