MD83 CAPT RPTS TCAS RA WITH 2 DC9'S IN ZAU AIRSPACE.

Narrative

THE EVENT STARTED WITH A CALL FROM ZAU TO TURN TO A HDG OF 360 DEGS FROM OUR CURRENT HDG OF APPROX 95 DEGS. THIS OF COURSE GOT MY ATTN AND I IMMEDIATELY STARTED A 25 DEG ANGLE OF BANK TURN WITH THE AUTOPLT ENGAGED. ABOUT 20 DEGS INTO THE TURN THE TCAS CALLED OUT THE 'TFC-TFC ALERT.' I AND THE FO WASTED ABOUT 3-4 SECONDS LOOKING AT THE MIDDLE RADAR DISPLAY BEFORE REALIZING THAT THIS WAS A FORMER ACR A WITH THE SMALLER DISPLAY ON EACH OF OUR INST PANELS. AT THAT POINT THERE WAS AN ACFT AT 2 O'CLOCK POS 400 FT HIGH AT APPROX 6-7 NM APCHING US (A DC9). NO SOONER DID THE 'TFC' WARNING GO OFF; THE TCAS CALLED OUT 'DSND' WITH A RATE OF 1800-2200 FPM. I DISENGAGED THE AUTOPLT AND STARTED A DSCNT AS MY FO TOLD CTR THAT WE WERE RESPONDING TO AN RA. NO SOONER DID I GET ESTABLISHED IN THE DSCNT WHEN THE TCAS CALLED OUT 'MONITOR VERT SPD' CALLED FOR A 0-400 FPM RATE OF CLB. I STOPPED MY DSCNT AT ABOUT FL322 AND SAW A SECOND JET (ALSO A DC9) COME OUT OFF MY LOWER L SIDE WHICH IS EVIDENTLY WHAT CAUSED THE TCAS TO STOP MY DSCNT FOR THE FIRST CONFLICT. THIS JET APPEARED TO BE LESS THAN 1000 FT CLRNC AND POSSIBLY IN THE 500-700 FT RANGE. THIS ALL TOOK PLACE IN THE PERIOD OF 15-20 SECONDS MAX. AFTER CLR OF BOTH CONFLICTS WE RPTED OUR ALT (APPROX FL322) AND GOT CLRNC TO CLB BACK UP TO OUR ALT OF FL330. THE FO QUERIED CTR ON WHAT TRANSPIRED AND THEY RESPONDED THAT THE JET THAT WAS ABOVE US AT OUR 2 O'CLOCK POS HAD NOT LEVELED AT HIS ASSIGNED ALT. WE CONTINUED ON TO ORD WITH NO FURTHER INCIDENT AND THERE WERE NO INJURIES TO OUR CABIN CREW OR PAX. REVIEW OF MY ACTIONS: GENERALLY I FELT THAT I DID A GOOD JOB BUT I WASTED PRECIOUS SECONDS LOOKING AT THE WRONG DISPLAY FROM MANY YEARS OF FLYING THE STANDARD MD80 ACFT WITH THE CTR MOUNTED TCAS. I SHOULD HAVE RPTED A NEAR MID-AIR WITH CTR. I GUESS I DIDN'T BECAUSE CTR SAID IT WASN'T OUR FAULT AND WE WERE RELIEVED THAT THE EVENT ENDED SUCCESSFULLY. REVIEW OF THE TCAS EQUIP: WORKED GREAT BY KEEPING US CLR OF 2 CONFLICTS. THE FORMER ACR A DISPLAYS (IN MY OPINION) ARE GREATLY INFERIOR TO THE STANDARD DISPLAYS IN SIZE; LOCATION AND RANGE. IT IS MY RECOMMENDATION THAT ALL MD80 ACFT SHOULD BE EQUIPPED WITH THE STANDARD; CTR MOUNTED 40 NM DISPLAYS SO AS TO AVOID A POTENTIALLY CATASTROPHIC INCIDENT WHERE THE PLT DID NOT HAVE THE LUXURY OF 3-4 SECONDS TRYING TO FIND THE DISPLAY.