Narrative:

We were on a heading of 180 degrees assigned from nassau approach in IMC WX just north of the island. We were in a descent cleared from 9000 ft to 3000 ft. There was a thunderstorm just north by northwest of the field and nassau approach seemed to be extremely busy. There was never a break in radio communications on the frequency. As we were descending through around 7500 ft the first officer noted TCAS traffic at one 1-2 O'clock position showing 500 ft below us and descending with a constant bearing and decreasing range. I could not talk to approach due to frequency saturation. The first officer correctly kicked off the autoplt and we both monitored the traffic. The aircraft continued to close at a constant 500 ft below and descending. We decided to stop our descent rate and began a climb to gain separation from the traffic. Still unable to get a word in on the frequency. As we were leveling off and starting to climb; we got a TCAS TA and at the same time a frantic call from nassau approach to stop descent at 7000 ft. We informed the controller hat we had already stopped our descent and were in a climb to avoid traffic. The controller then stated something to the effect of 'I called that traffic to you before;' which she had absolutely not done and we were IMC anyway. I believe the controller was overwhelmed and completely lost situational awareness. The first officer did an excellent job in using TCAS to prevent a potential midair. I can't be sure how close to the traffic we actually got; but I would estimate 1-2 mi at 500 ft.

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Original NASA ASRS Text

Title: AN A319 FLT CREW DSNDING FOR APCH AT MYNN NOTICED TFC ON TCAS. THEY INITIATED A CLB TO AVOID CONFLICT.

Narrative: WE WERE ON A HDG OF 180 DEGS ASSIGNED FROM NASSAU APCH IN IMC WX JUST N OF THE ISLAND. WE WERE IN A DSCNT CLRED FROM 9000 FT TO 3000 FT. THERE WAS A TSTM JUST N BY NW OF THE FIELD AND NASSAU APCH SEEMED TO BE EXTREMELY BUSY. THERE WAS NEVER A BREAK IN RADIO COMS ON THE FREQ. AS WE WERE DSNDING THROUGH AROUND 7500 FT THE FO NOTED TCAS TFC AT ONE 1-2 O'CLOCK POS SHOWING 500 FT BELOW US AND DSNDING WITH A CONSTANT BEARING AND DECREASING RANGE. I COULD NOT TALK TO APCH DUE TO FREQ SATURATION. THE FO CORRECTLY KICKED OFF THE AUTOPLT AND WE BOTH MONITORED THE TFC. THE ACFT CONTINUED TO CLOSE AT A CONSTANT 500 FT BELOW AND DSNDING. WE DECIDED TO STOP OUR DSCNT RATE AND BEGAN A CLB TO GAIN SEPARATION FROM THE TFC. STILL UNABLE TO GET A WORD IN ON THE FREQ. AS WE WERE LEVELING OFF AND STARTING TO CLB; WE GOT A TCAS TA AND AT THE SAME TIME A FRANTIC CALL FROM NASSAU APCH TO STOP DSCNT AT 7000 FT. WE INFORMED THE CTLR HAT WE HAD ALREADY STOPPED OUR DSCNT AND WERE IN A CLB TO AVOID TFC. THE CTLR THEN STATED SOMETHING TO THE EFFECT OF 'I CALLED THAT TFC TO YOU BEFORE;' WHICH SHE HAD ABSOLUTELY NOT DONE AND WE WERE IMC ANYWAY. I BELIEVE THE CTLR WAS OVERWHELMED AND COMPLETELY LOST SITUATIONAL AWARENESS. THE FO DID AN EXCELLENT JOB IN USING TCAS TO PREVENT A POTENTIAL MIDAIR. I CAN'T BE SURE HOW CLOSE TO THE TFC WE ACTUALLY GOT; BUT I WOULD ESTIMATE 1-2 MI AT 500 FT.

Data retrieved from NASA's ASRS site as of January 2009 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.