Narrative:

During descent into ont, shortly after crossing hitop intersection, we were given a clearance to maintain 8000' and a heading for vectors to the ILS 26L approach. After level off ont approach control announced, 'air carrier X, traffic alert, turn left immediately. Traffic 2 O'clock, same altitude!' the captain rolled into a left bank and in the turn the second officer spotted a light small aircraft Y at 10 O'clock, same altitude, not our 2 O'clock position. We determined that it was necessary to descend to avoid the traffic. Approximately 15 seconds after the controller's alert we informed ATC that the traffic was 'in sight' and that we were required to descend to 7200' to avoid the small transport Y, but we were now able to climb back to 8000'. The controller responded with, 'no, just continue your descent to 4000', present heading.' note: this incident may have been more serious if it was not for the third set of eyes of the second officer. Callback conversation with reporter revealed the following: reporter states that after initial report was sent in he wanted to add that the turn call of the TRACON controller was in the correct direction. The reason he thinks the controller gave traffic at 2 O'clock instead of 10 O'clock was that the controller had just talked to the small aircraft aircraft Y and asked him his altitude. He then noted the air carrier at the small aircraft's 2 O'clock position and in the urgency of the call on traffic gave the '2' instead of '10.' not really an operational error so far as pilot required action.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT WITH VFR SMA. GOOD TRAFFIC CALL BY ATC ON TRAFFIC ALTHOUGH ACFT POSITION WAS WRONG.

Narrative: DURING DSCNT INTO ONT, SHORTLY AFTER XING HITOP INTXN, WE WERE GIVEN A CLRNC TO MAINTAIN 8000' AND A HDG FOR VECTORS TO THE ILS 26L APCH. AFTER LEVEL OFF ONT APCH CTL ANNOUNCED, 'ACR X, TFC ALERT, TURN LEFT IMMEDIATELY. TFC 2 O'CLOCK, SAME ALT!' THE CAPT ROLLED INTO A LEFT BANK AND IN THE TURN THE S/O SPOTTED A LIGHT SMA Y AT 10 O'CLOCK, SAME ALT, NOT OUR 2 O'CLOCK POS. WE DETERMINED THAT IT WAS NECESSARY TO DSND TO AVOID THE TFC. APPROX 15 SECS AFTER THE CTLR'S ALERT WE INFORMED ATC THAT THE TFC WAS 'IN SIGHT' AND THAT WE WERE REQUIRED TO DSND TO 7200' TO AVOID THE SMT Y, BUT WE WERE NOW ABLE TO CLB BACK TO 8000'. THE CTLR RESPONDED WITH, 'NO, JUST CONTINUE YOUR DSCNT TO 4000', PRESENT HDG.' NOTE: THIS INCIDENT MAY HAVE BEEN MORE SERIOUS IF IT WAS NOT FOR THE THIRD SET OF EYES OF THE S/O. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES THAT AFTER INITIAL RPT WAS SENT IN HE WANTED TO ADD THAT THE TURN CALL OF THE TRACON CTLR WAS IN THE CORRECT DIRECTION. THE REASON HE THINKS THE CTLR GAVE TFC AT 2 O'CLOCK INSTEAD OF 10 O'CLOCK WAS THAT THE CTLR HAD JUST TALKED TO THE SMA ACFT Y AND ASKED HIM HIS ALT. HE THEN NOTED THE ACR AT THE SMA'S 2 O'CLOCK POS AND IN THE URGENCY OF THE CALL ON TFC GAVE THE '2' INSTEAD OF '10.' NOT REALLY AN OPERROR SO FAR AS PLT REQUIRED ACTION.

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.