Narrative:

Medium large transport X was on downwind for runway 14R at O'hare. Copilot was flying. Aircraft was at 5000', 210 KTS and on a 320 degree heading. Controller gave us a right turn to 90 degree and I acknowledged. As we started our turn we saw large transport Y at 1 O'clock and level with us. Controller said 'hurry your turn to 130 degree' and we acknowledged. A supervisor then came on and asked us to confirm we were descending to 3000'. I said, 'no, but we'll start down now.' the supervisor asked if we had large transport Y in sight and I said we did. Supervisor gave us a 50 degree heading to pass behind large transport Y. We were then slowed to 170 KTS. After passing behind large transport Y we were given a vector back to final and cleared for a visual to 14R. I talked to the supervisor on the phone to see what had happened. At sometime on downwind there must have been a blocked transmission to us--to descend to 3000' and slow to 170 KTS. I did not receive nor acknowledge this call. Because we were at 5000' and 210 KTS a conflict occurred. Supplemental information from acn 89816. I remember hearing a blocked transmission on downwind, and it may have been for us, but the controller may have assumed that it was received (but not acknowledged). Our downwind speed of 210 was incompatible with sequencing 170 KT aircraft, but the controller might have been distracted and thought the sequencing was acceptable.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACR MLG VECTORED INTO CONFLICT WITH ACR LGT WHEN DESCENT CLRNC WAS NOT RECEIVED, RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: MLG X WAS ON DOWNWIND FOR RWY 14R AT O'HARE. COPLT WAS FLYING. ACFT WAS AT 5000', 210 KTS AND ON A 320 DEG HDG. CTLR GAVE US A R TURN TO 90 DEG AND I ACKNOWLEDGED. AS WE STARTED OUR TURN WE SAW LGT Y AT 1 O'CLOCK AND LEVEL WITH US. CTLR SAID 'HURRY YOUR TURN TO 130 DEG' AND WE ACKNOWLEDGED. A SUPERVISOR THEN CAME ON AND ASKED US TO CONFIRM WE WERE DSNDING TO 3000'. I SAID, 'NO, BUT WE'LL START DOWN NOW.' THE SUPERVISOR ASKED IF WE HAD LGT Y IN SIGHT AND I SAID WE DID. SUPERVISOR GAVE US A 50 DEG HDG TO PASS BEHIND LGT Y. WE WERE THEN SLOWED TO 170 KTS. AFTER PASSING BEHIND LGT Y WE WERE GIVEN A VECTOR BACK TO FINAL AND CLRED FOR A VISUAL TO 14R. I TALKED TO THE SUPERVISOR ON THE PHONE TO SEE WHAT HAD HAPPENED. AT SOMETIME ON DOWNWIND THERE MUST HAVE BEEN A BLOCKED XMISSION TO US--TO DSND TO 3000' AND SLOW TO 170 KTS. I DID NOT RECEIVE NOR ACKNOWLEDGE THIS CALL. BECAUSE WE WERE AT 5000' AND 210 KTS A CONFLICT OCCURRED. SUPPLEMENTAL INFO FROM ACN 89816. I REMEMBER HEARING A BLOCKED XMISSION ON DOWNWIND, AND IT MAY HAVE BEEN FOR US, BUT THE CTLR MAY HAVE ASSUMED THAT IT WAS RECEIVED (BUT NOT ACKNOWLEDGED). OUR DOWNWIND SPD OF 210 WAS INCOMPATIBLE WITH SEQUENCING 170 KT ACFT, BUT THE CTLR MIGHT HAVE BEEN DISTRACTED AND THOUGHT THE SEQUENCING WAS ACCEPTABLE.

Data retrieved from NASA's ASRS site as of August 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.