ACR HAS NMAC NEAR FLL.

Narrative

WHILE ON CLBOUT FROM FLL/HOLLYWOOD ARPT; FL; WE WERE GIVEN A CLB TO 6000 FT MSL. DEP THEN AMENDED OUR ALT TO 4000 FT; GAVE US A R TURN TO THE N; AND SAID VFR TFC WOULD BE AT OUR 2 O'CLOCK POS AT 4500 FT. WE ACQUIRED THE TFC ON TCASII AS WE CLBED THROUGH APPROX 3000 FT; BUT COULD NOT VISUALLY ACQUIRE HIM DUE TO A THIN CLOUD LAYER AT 4000 FT SEPARATING US. I COMMENTED THAT IT APPEARED HE WAS DSNDING; BASED ON THE TCASII ALT DIFFERENCE DISPLAY. ACCORDINGLY; WE SHALLOWED OUR CLB AS WE WENT THROUGH ABOUT 3300 FT. ABOUT THEN; WE RECEIVED A TCASII TA. I CONTINUED TO SEARCH VISUALLY FOR THE TFC OUT THE R SIDE; BUT THE CLOUD LAYER ABOVE US STILL BLOCKED MY VIEW. THEN I HEARD A RADIO EXCHANGE BTWN DEP AND THE CESSNA; SOMETHING TO THE EFFECT OF 'CESSNA XXX WHAT ARE YOU DOING? YOU CAN'T CHANGE ALTS WITHOUT ADVISING ME FIRST.' THE CESSNA MUMBLED SOMETHING ABOUT MAINTAINING CLOUD CLRNCS. THE TCASII STILL SHOWED HIM DSNDING. WE LEVELED AT ABOUT 3700 FT; THEN RECEIVED A TCASII RA TO DSND. WE BEGAN A SHALLOW DSCNT AND A SLIGHT L TURN; AND I ADVISED ATC WE WERE DSNDING FOR A TCASII RA. THE TCASII CONTINUED TO TELL US TO DSND; ATC WAS FRANTICALLY TELLING THE CESSNA TO GET BACK TO HIS ALT; AND A MOMENT LATER I SPOTTED THE TFC CONVERGING; ABOUT 100 FT BELOW US. I YELLED TO THE CAPT; 'I'VE GOT HIM; HE'S BELOW US! DON'T DSND!' HE REPLIED INCREDULOUSLY; 'BELOW US?!' WE RESUMED CLBING AS THE TFC WENT DIRECTLY UNDERNEATH US. WE INFORMED ATC THAT WE WERE CLR OF THE TFC; WERE CLBING AGAIN AND HAD JUST HAD A VERY CLOSE CALL. ATC GAVE THE CESSNA A PHONE NUMBER TO CALL WHEN HE LANDED. APPARENTLY; THE CESSNA DSNDED THROUGH OUR ALT SO RAPIDLY THAT THE TCASII COULD NOT KEEP UP -- NEVER GIVING US AN RA OTHER THAN 'DSND.' ANOTHER POINT OF INTEREST: HAD WE AGGRESSIVELY FOLLOWED THE TCASII DSND ADVISORY AND DSNDED QUICKLY INSTEAD OF INITIATING A SHALLOW DSCNT AS WE DID; WE MAY HAVE EASILY ENDED UP 100 FT LOWER; THUS CO-ALT AS WE CROSSED.