Narrative:

Upon initial contact given descent from 10000 ft to 5000 ft, 'expect runway 27.' shortly thereafter, told 'expect runway 18R and contact final controller.' 'final' controller was working many aircraft, 99% our company, and at least one with a similar sounding flight number. Assigned speed 210 KTS, then cleared to 4000 ft, heading 270 degrees. Leveling 4000 ft, assigned 3000 ft, slow to 180 KTS. I began a 500 FPM descent and allowed IAS to slowly decrease. At about 3500 ft, ATC cleared the flight with similar call sign '200 KTS and 2000 ft.' PF thought the speed, altitude assignment was for us and 'answered' ATC, blocking the other flight's acknowledgment. ATC corrected us, reclred the other flight, then asked our speed (200 KTS, decreasing). Then, in a very excited voice he said 'turn left heading 180 degrees now.' as we turned, we observed an opposite direction aircraft we had been watching, go over us approximately 1000 ft above. Remainder of flight was normal vectors for the approach. On postflt the 3 of us (flight crew) discussed event. None of us believe we missed a heading assignment. Possibilities are ATC forgot due to workload and similar sounding call signs, or he gave it to us during the blocked transmission, or we may (not likely) have missed it. We don't believe there was a traffic conflict this time, but we have no way of knowing (no TCASII). If we are correct in that we did not miss the heading assignment, then the most likely factor would be ATC workload and with similar call signs ATC thought he gave us a new heading, or he gave '180 KTS' instead of '180 degrees,' which he might have meant. The company 'airline scheduling' department controls flight numbering, and with approximately 130 flts arriving in an approximately 2 hour period there are bound to be similar sounding call signs, but perhaps there is something they can do to reduce the number. Several pilots have suggested this through our internal flight safety department, but the company is reluctant to change flight numbering for now due to the 'system' currently in place.

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Original NASA ASRS Text

Title: CREW MISSED A HEADING CHANGE DURING DSCNT AND HAD A CONFLICT AIRBORNE WITH ANOTHER ACFT.

Narrative: UPON INITIAL CONTACT GIVEN DSCNT FROM 10000 FT TO 5000 FT, 'EXPECT RWY 27.' SHORTLY THEREAFTER, TOLD 'EXPECT RWY 18R AND CONTACT FINAL CTLR.' 'FINAL' CTLR WAS WORKING MANY ACFT, 99% OUR COMPANY, AND AT LEAST ONE WITH A SIMILAR SOUNDING FLT NUMBER. ASSIGNED SPD 210 KTS, THEN CLRED TO 4000 FT, HEADING 270 DEGS. LEVELING 4000 FT, ASSIGNED 3000 FT, SLOW TO 180 KTS. I BEGAN A 500 FPM DSCNT AND ALLOWED IAS TO SLOWLY DECREASE. AT ABOUT 3500 FT, ATC CLRED THE FLT WITH SIMILAR CALL SIGN '200 KTS AND 2000 FT.' PF THOUGHT THE SPD, ALT ASSIGNMENT WAS FOR US AND 'ANSWERED' ATC, BLOCKING THE OTHER FLT'S ACKNOWLEDGMENT. ATC CORRECTED US, RECLRED THE OTHER FLT, THEN ASKED OUR SPD (200 KTS, DECREASING). THEN, IN A VERY EXCITED VOICE HE SAID 'TURN L HDG 180 DEGS NOW.' AS WE TURNED, WE OBSERVED AN OPPOSITE DIRECTION ACFT WE HAD BEEN WATCHING, GO OVER US APPROX 1000 FT ABOVE. REMAINDER OF FLT WAS NORMAL VECTORS FOR THE APCH. ON POSTFLT THE 3 OF US (FLC) DISCUSSED EVENT. NONE OF US BELIEVE WE MISSED A HEADING ASSIGNMENT. POSSIBILITIES ARE ATC FORGOT DUE TO WORKLOAD AND SIMILAR SOUNDING CALL SIGNS, OR HE GAVE IT TO US DURING THE BLOCKED XMISSION, OR WE MAY (NOT LIKELY) HAVE MISSED IT. WE DON'T BELIEVE THERE WAS A TFC CONFLICT THIS TIME, BUT WE HAVE NO WAY OF KNOWING (NO TCASII). IF WE ARE CORRECT IN THAT WE DID NOT MISS THE HEADING ASSIGNMENT, THEN THE MOST LIKELY FACTOR WOULD BE ATC WORKLOAD AND WITH SIMILAR CALL SIGNS ATC THOUGHT HE GAVE US A NEW HEADING, OR HE GAVE '180 KTS' INSTEAD OF '180 DEGS,' WHICH HE MIGHT HAVE MEANT. THE COMPANY 'AIRLINE SCHEDULING' DEPT CTLS FLT NUMBERING, AND WITH APPROX 130 FLTS ARRIVING IN AN APPROX 2 HR PERIOD THERE ARE BOUND TO BE SIMILAR SOUNDING CALL SIGNS, BUT PERHAPS THERE IS SOMETHING THEY CAN DO TO REDUCE THE NUMBER. SEVERAL PLTS HAVE SUGGESTED THIS THROUGH OUR INTERNAL FLT SAFETY DEPT, BUT THE COMPANY IS RELUCTANT TO CHANGE FLT NUMBERING FOR NOW DUE TO THE 'SYS' CURRENTLY IN PLACE.

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.