3 ACFT SCENARIO AT FL350; FL330; AND FL310. ACFT AT FL330 TAKES DSCNT CLRNC TO FL280 MEANT FOR ACFT AT FL350 AND CONFLICTS WITH ACFT AT FL310.

Narrative

2 ACFT WITH SIMILAR CALL SIGNS ACR X AND ACR Z. ACR Z WAS ON FREQ AND CLRED DIRECT IIU HEHAW 3 BNA AND WAS INITIALLY AT FL350 BUT REQUESTED LOWER ALT TO GET OUT OF CHOPPY AIR. HE WAS DSNDED TO FL310 AND LATER TO FL280. ACR X WAS FLYING DQN MIZAR 3 DTW AND CAME ON FREQ AT FL330 AND REQUESTED LOWER DUE TO CHOPPY AIR (LIGHT TO MODERATE). ACR Y WAS AT FL310 FROM PIT ROD-XXX SFO. WX WAS A FACTOR AS WAS THE CHOPPY AIR; WHICH WAS FORCING MANY FLTS DOWN INTO OUR AIRSPACE COMPACTING THE SIT. ADDITIONAL FLTS WERE BEING PUT INTO OUR SECTOR GOING TO THE EAST COAST BECAUSE ZDC (OPERATING ON DSR) WOULD NOT ACCEPT THESE FLTS ON THE SOUTHERN ROUTINGS. ACR Z WAS ISSUED CLRNC TO DSND TO FL280; BUT ACR X (WHO WAS WANTING TO DSND) TOOK THE CLRNC AND STARTED THE DSCNT TO FL280. I WAS ON A LINE TALKING TO ZOB AT THE TIME THE CLRNC WAS GIVEN AND DID NOT HEAR THE READBACK. THE RADAR CTLR THOUGHT THE CORRECT ACFT RESPONDED TO THE CLRNC BUT WAS DISTR BY THE NOISE AROUND HIM SINCE THE FFO RADAR SCOPE SITS NEXT TO THE DAY RADAR SCOPE IN OUR DSR POD. BOTH SECTORS WERE VERY BUSY ON THIS SHIFT. ACR X DSNDED INTO ACR Y AIRSPACE AND RADAR CTLR GAVE IMMEDIATE CLRNC TO FL280 TO ACR X; BUT THE ACR X RECEIVED AN RA ALERT ON TCASII AND CLBED BACK TO FL330; BUT SEPARATION HAD BEEN LOST. CORRECTIVE ACTIONS: 1) MOVE DAY OR FFO RADAR SCOPE AWAY FROM EACH OTHER (BOTH ARE HIGH VOLUME SECTORS). 2) NEED A BETTER PLAN TO ELIMINATE SIMILAR CALL SIGNS OPERATING IN SAME REGION OF COUNTRY AT THE SAME TIME. 3) IN MY 30 YRS OF FAA EXPERIENCE; PLT ATTN TO CTLRS IS AT THE WORST LEVEL I HAVE SEEN. ACTION NEEDS TO BE TAKEN. SUPPLEMENTAL INFO FROM ACN 469723: THE FOLLOWING EVENT OCCURRED ON A SCHEDULED ACR X FROM BNA TO DTW APR/XA/00 AT XA00. THE ACFT WAS A B737-700. I WAS THE FO AND ALSO THE PF ON THIS FLT. THE CREW CONSISTED OF 2 PLTS AND 3 FLT ATTENDANTS. WHILE ENRTE TO DTW; OUR FLT (ACR X) WAS CLRED DIRECT TO DQN VOR TO FLY THE REMAINDER OF THE MIZAR 3 ARR. WE HAD EXPERIENCED CONTINUOUS LIGHT TO OCCASIONAL MODERATE TURB AT OUR ASSIGNED ALT OF FL330 AND HAD REQUESTED A LOWER ALT DUE TO THE FLT CONDITIONS. APPROX 20 DME PRIOR TO THE DQN VOR; ZID ON FREQ 125.07 ISSUED THE CLRNC 'ACR X DSND AND MAINTAIN FL260.' THE PNF (CAPT) READ BACK THE CLRNC 'ROGER; ACR X DEPARTING FL330 FOR FL260.' BOTH PF AND PNF ACKNOWLEDGED THE CLRNC TO EACH OTHER AND THE PF (FO) INITIATED THE DSCNT. I SPECIFICALLY REMEMBER THIS CLRNC BECAUSE THE CAPT ASKED ME IF I WANTED HIM TO ENTER THE NEW CRUISE ALT INTO THE FMC AND I STATED THAT I WOULD INDEED PREFER THAT HE DO SO. AS OUR FLT PASSED OVER THE DQN VOR TO PROCEED OUTBOUND ON THE 360 DEG RADIAL; AND PASSING FL300 AT 1000 FPM RATE OF DSCNT; ZID QUERIED 'ACR X VERIFY YOUR ASSIGNED ALT.' THE PNF ACKNOWLEDGED WITH 'ACR X ASSIGNED FL260.' ZID CTLR REPLIED 'ACR X DSND IMMEDIATELY TO FL280 -- YOU HAVE TFC AT 12:30 O'CLOCK POS; 5 MI.' AT THE TIME THIS IMMEDIATE CLRNC WAS GIVEN BY ZID; I NOTICED A 'YELLOW' TCASII TFC TARGET AT 12:30 O'CLOCK POS AND 5 MI. THE PNF KEYED THE MIKE AND QUERIED THE ZID CTLR'S CLRNC WITH 'CONFIRM YOU WANT ACR X TO DSND TO FL280.' THE ZID CTLR REPLIED 'ACR X DSND IMMEDIATELY TO FL280; YOU HAVE TFC AT 12:30 O'CLOCK POS; LESS THAN 1 MI.' WE SIMULTANEOUSLY RECEIVED AN RA TO CLB; SO THE PF COMPLIED WITH THE RA AND STARTED AN IMMEDIATE CLB -- NOT A DSCNT; AS INSTRUCTED BY THE ZID CTLR TO AVOID TFC (AN AIRBUS THAT APPEARED TO BE 1-2 MI IN FRONT OF THE ACFT AND APPROX 400 FT BELOW OUR ALT). THE PF INITIATED A R CLBING TURN TO KEEP THE TFC IN SIGHT. THE ACFT CLBED APPROX 1000 FT AND TURNED APPROX 20 DEGS TO THE R. THE PNF KEYED HIS MIKE AND STATED 'ACR X IS CLBING TO AVOID TFC IN COMPLIANCE WITH OUR RA.' AS THE ACR Y ACFT PASSED BELOW FROM R TO L; THE PNF QUERIED ZID 'TFC NOW NO FACTOR; WHAT ALT DO YOU WANT ACR X TO MAINTAIN?' ZID INSTRUCTED 'ACR X NOW DSND AND MAINTAIN FL240.' WHILE THIS EVENT OCCURRED; THERE WAS ANOTHER COMPANY ACR Z ACFT ON FREQ. HIS CALL SIGN WAS ACR Z OR SIMILAR SOUNDING CALL SIGN. THERE WERE RADIO EXCHANGES BTWN ZID AND THE OTHER COMPANY ACFT; HOWEVER; I WAS BUSY WITH OUR IMMEDIATE CIRCUMSTANCE AND DO NOT REMEMBER THE EXACT RADIO EXCHANGES. IT WAS EVIDENT; HOWEVER; THAT THERE WAS SOME CONFUSION WITH OUR ACFT; COMPANY ACFT; AND THE CTLR. IT WAS THIS CONFUSION I FELT THAT LED THE CTLR TO ISSUE THE CLRNC THAT WAS CONTRAINDICATED BY THE TCASII RA. AT THE TIME; ZID WAS VERY BUSY WITH NUMEROUS ACFT -- 2 OF WHICH WERE COMPANY ACFT WITH SIMILAR SOUNDING CALL SIGNS. MY PERCEPTION IS THAT THE ZID CTLR ISSUED CLRNC FOR ACR X (OUR ACFT) WHEN HE MEANT TO GIVE A CLRNC TO ACR Z. EVEN THOUGH WE READ BACK THE CLRNC WITH OUR CALL SIGN; ACR X; THE CTLR DID NOT CATCH THE ERROR. AS WE PROCEEDED TOWARD DTW WE WERE ISSUED A FREQ CHANGE TO ZOB 126.97. AS WE WERE CLRED TO ANOTHER FREQ; THE ZID CTLR STATED 'ACR X; WHAT HAPPENED WAS THAT YOU TOOK YOUR COMPANY'S CLRNC.' THE PF REPLIED 'WE READ BACK OUR CALL SIGN ACR X WITH THE CLRNC.' THERE WAS NO REPLY FROM ZID SO WE SWITCHED FREQS AND RPTED IN TO ZOB. THE REMAINDER OF THE FLT WAS UNEVENTFUL.