Narrative:

We were on an IFR flight plan from eyw to sfb in mixed conditions when told to descend from 9000 ft. About 1 min or so later, ZMA called and said to expedite descent for traffic, and got upset saying they tried calling several times without a reply from us. When they handed us off to orlando, they did the same thing and said they tried several times to reach us. There were 2 pilots on board and neither of us heard these multiple calls. We fly the same route all the time and have never missed a call from ATC. It was obvious that the controller was working more than 1 frequency. We missed the traffic by 900 ft vertically and at least 700 ft horizontally. The traffic was VFR at 7500 ft. We were about 6650 ft. If the traffic was more than 1000 ft vertically, we wouldn't be making this report. The traffic didn't concern us because our TCASII didn't show a conflict, our concern was the blame for missed calls. I think the controller using more than 1 frequency played a large role in this. His attempts to call us couldn't have been on our frequency because we heard all xmissions on it. I can see missing 1 call at the most, but repeated? After the first complaint by ATC of not responding, we were extremely alert for our call sign. When ATC again said we didn't respond after repeated calls for frequency change, we knew for sure it was their mistake. On the other side though, ATC was very busy and I'm sure had his hands full. Another controller to help him would have definitely helped the situation.

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Original NASA ASRS Text

Title: IFR C414 PLT IS QUESTIONED BY ZMA CTLR REGARDING LACK OF RESPONSE TO ATC XMISSIONS.

Narrative: WE WERE ON AN IFR FLT PLAN FROM EYW TO SFB IN MIXED CONDITIONS WHEN TOLD TO DSND FROM 9000 FT. ABOUT 1 MIN OR SO LATER, ZMA CALLED AND SAID TO EXPEDITE DSCNT FOR TFC, AND GOT UPSET SAYING THEY TRIED CALLING SEVERAL TIMES WITHOUT A REPLY FROM US. WHEN THEY HANDED US OFF TO ORLANDO, THEY DID THE SAME THING AND SAID THEY TRIED SEVERAL TIMES TO REACH US. THERE WERE 2 PLTS ON BOARD AND NEITHER OF US HEARD THESE MULTIPLE CALLS. WE FLY THE SAME RTE ALL THE TIME AND HAVE NEVER MISSED A CALL FROM ATC. IT WAS OBVIOUS THAT THE CTLR WAS WORKING MORE THAN 1 FREQ. WE MISSED THE TFC BY 900 FT VERTLY AND AT LEAST 700 FT HORIZLY. THE TFC WAS VFR AT 7500 FT. WE WERE ABOUT 6650 FT. IF THE TFC WAS MORE THAN 1000 FT VERTLY, WE WOULDN'T BE MAKING THIS RPT. THE TFC DIDN'T CONCERN US BECAUSE OUR TCASII DIDN'T SHOW A CONFLICT, OUR CONCERN WAS THE BLAME FOR MISSED CALLS. I THINK THE CTLR USING MORE THAN 1 FREQ PLAYED A LARGE ROLE IN THIS. HIS ATTEMPTS TO CALL US COULDN'T HAVE BEEN ON OUR FREQ BECAUSE WE HEARD ALL XMISSIONS ON IT. I CAN SEE MISSING 1 CALL AT THE MOST, BUT REPEATED? AFTER THE FIRST COMPLAINT BY ATC OF NOT RESPONDING, WE WERE EXTREMELY ALERT FOR OUR CALL SIGN. WHEN ATC AGAIN SAID WE DIDN'T RESPOND AFTER REPEATED CALLS FOR FREQ CHANGE, WE KNEW FOR SURE IT WAS THEIR MISTAKE. ON THE OTHER SIDE THOUGH, ATC WAS VERY BUSY AND I'M SURE HAD HIS HANDS FULL. ANOTHER CTLR TO HELP HIM WOULD HAVE DEFINITELY HELPED THE SIT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.