WDB ACFT ON APCH ASSIGNED TWR FREQ ON WHICH THERE WAS NO ANSWER. FLC COULD HEAR OTHER XMISSIONS; BUT TWR DIDN'T ANSWER THEIR LNDG REQUEST. RPTR HAD TO GAR RESULTING IN A CONFLICT WITH ANOTHER ACFT. TWR CTLR THOUGHT HE HAD CLRED RPTR ACFT TO LAND.

Narrative

I WAS FO ON FLT. WE WERE CLRED FOR THE ILS 12 TO DULLES AND TOLD TO SWITCH TWR 128.42. TWR TOLD US THE FREQ FOR RWY 12 WAS 120.1. I TRIED TO CALL TWR TWICE AT THE MARKER (ARCOA); ONCE AT ABOUT 3 MI AND SEVERAL TIMES SHORT FINAL. THE CAPT TRIED AS WELL; THINKING MAYBE MY MIKE HAD FAILED. I ALSO TRIED CONTACT ON 128.42 ON OUR OTHER RADIO. WE COULD HEAR TWR DIRECTING OTHER TFC. IT SOUNDED LIKE SOMEONE MISSED A HIGH SPD THAT RESULTED IN THE DISRUPTION OF THE PLANNED FLOW OF ARR/DEP TFC. WE COULD NOT HEAR SOME OF THE OTHER ACFT TWR WAS TALKING TO; PERHAPS THEY WERE ON THE OTHER FREQ. WE EXECUTED A MISSED APCH AT APPROX 100 FT DUE TO NO LNDG CLRNC. DURING CLB OUT AT APPROX 500 FT AGL; THE SO POINTED OUT TFC. A B737 WAS PASSING L TO R; OUR ALT AND CLBING. SEPARATION WAS APPROX 900 FT OR LESS AND WOULD HAVE BEEN MUCH CLOSER HAD WE NOT IMMEDIATELY TURNED L AND DSNDED. AFTER WE STARTED MANEUVERING WE DID GET A TA ON THE TCASII AND A GPWS 'SINK RATE.' ONCE CLR OF THE TFC; TWR CALLED US AND DIRECTED A TURN TO 040 DEGS. WE ASKED FOR AN ALT AND THEN WERE VECTORED FOR AN APCH TO RWY 19R. WE SPOKE TO THE TWR SUPVR AND HE TOLD US THAT THE CTLR THOUGHT HE HAD CLRED US TO LAND. I DO NOT KNOW WHY HE DIDN'T RESPOND TO ANY OF OUR CALLS. THE DUAL FREQ OPS SEEMED TO ADD TO THE CONFUSION ON THE TWR FREQ. WE'RE NOT SURE IF THE B737 JET WAS OFF A MISSED OR DEPARTING. IN HINDSIGHT; IF I WOULD HAVE CALLED THE MISSED TO TWR IMMEDIATELY AND HE HEARD IT; UNLIKE ALL THE OTHER CALLS; PERHAPS HE COULD HAVE DIRECTED US OR B737 AWAY FROM EACH OTHER.