Narrative:

Air carrier X was level at 6000'. Turned on a base leg (right). Air carrier Y at 6000' on modified base to final (left). Air carrier X on right base was descended to 5000' with the turn to base. Air carrier X acknowledged transmission. 1 min, 10 seconds later air carrier X was still level at 6000'. Situation would not have occurred if pilot had complied with instructions promptly. Supplemental information from acn 148336: air carrier X inbound to okc for landing in an medium large transport aircraft. We were originally on the initial approach control frequency and on an approximately heading to the OM from the west. We were descending to 6000'. We heard another aircraft say that he was running out of time and needed 1 more ILS approach to complete. We were then turned to a heading of north, given descent to 5000', sent to the final controller and told that we were fourth. (After we landed we were told that the change was due to an aircraft declaring minimum fuel. We both had the feeling that the incident began with an FAA light transport trying to get in 1 more approach and messing up the sequence already established.) after flying about 15 DME north of the okc VOR we were given a turn to the northeast and then to 090 degrees. We had been descending. At 6000' we called the traffic in sight and were told to turn southeast and follow the traffic to the runway. At the time of sighting medium large transport was about 1-2 mi away on a direct collision course at essentially the same altitude. The direction to follow the medium large transport flight to the runway was impossible because of the position and proximity of the 2 aircraft. We pushed over moderately to get down to 5000' and turned southeast. Aircraft Z turned northwest and flew within 100-200' horizontal and 300-600' vertical. After passing there still was confusion with the controller's commands because he apparently thought we were air carrier Z and vise verse. After that, we received clearance for a visibility approach with an uneventful landing.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR. ACR X FAILED TO COMPLY WITH ACT CLRNC. OPERATIONAL DEVIATION.

Narrative: ACR X WAS LEVEL AT 6000'. TURNED ON A BASE LEG (RIGHT). ACR Y AT 6000' ON MODIFIED BASE TO FINAL (LEFT). ACR X ON RIGHT BASE WAS DSNDED TO 5000' WITH THE TURN TO BASE. ACR X ACKNOWLEDGED XMISSION. 1 MIN, 10 SECS LATER ACR X WAS STILL LEVEL AT 6000'. SITUATION WOULD NOT HAVE OCCURRED IF PLT HAD COMPLIED WITH INSTRUCTIONS PROMPTLY. SUPPLEMENTAL INFO FROM ACN 148336: ACR X INBND TO OKC FOR LNDG IN AN MLG ACFT. WE WERE ORIGINALLY ON THE INITIAL APCH CTL FREQ AND ON AN APPROX HDG TO THE OM FROM THE W. WE WERE DSNDING TO 6000'. WE HEARD ANOTHER ACFT SAY THAT HE WAS RUNNING OUT OF TIME AND NEEDED 1 MORE ILS APCH TO COMPLETE. WE WERE THEN TURNED TO A HDG OF N, GIVEN DSNT TO 5000', SENT TO THE FINAL CTLR AND TOLD THAT WE WERE FOURTH. (AFTER WE LANDED WE WERE TOLD THAT THE CHANGE WAS DUE TO AN ACFT DECLARING MINIMUM FUEL. WE BOTH HAD THE FEELING THAT THE INCIDENT BEGAN WITH AN FAA LTT TRYING TO GET IN 1 MORE APCH AND MESSING UP THE SEQUENCE ALREADY ESTABLISHED.) AFTER FLYING ABOUT 15 DME N OF THE OKC VOR WE WERE GIVEN A TURN TO THE NE AND THEN TO 090 DEGS. WE HAD BEEN DSNDING. AT 6000' WE CALLED THE TFC IN SIGHT AND WERE TOLD TO TURN SE AND FOLLOW THE TFC TO THE RWY. AT THE TIME OF SIGHTING MLG WAS ABOUT 1-2 MI AWAY ON A DIRECT COLLISION COURSE AT ESSENTIALLY THE SAME ALT. THE DIRECTION TO FOLLOW THE MLG FLT TO THE RWY WAS IMPOSSIBLE BECAUSE OF THE POS AND PROX OF THE 2 ACFT. WE PUSHED OVER MODERATELY TO GET DOWN TO 5000' AND TURNED SE. ACFT Z TURNED NW AND FLEW WITHIN 100-200' HORIZ AND 300-600' VERT. AFTER PASSING THERE STILL WAS CONFUSION WITH THE CTLR'S COMMANDS BECAUSE HE APPARENTLY THOUGHT WE WERE ACR Z AND VISE VERSE. AFTER THAT, WE RECEIVED CLRNC FOR A VIS APCH WITH AN UNEVENTFUL LNDG.

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.