Narrative:

On downwind to runway 22L at ewr, at 5000 ft, we were told to descend to 4000 ft. We started our descent and the TCASII gave us a TA. We observed traffic at 900 ft below us on TCASII. He appeared to be right under our left wing. At first I thought he may be going in the opposite direction but his position did not change, so I kicked off the autoplt and began to climb back up to 5000 ft. At this time the controller asked if we were maintaining 5000 ft. We asked the controller about the other aircraft, and he said that it was not under his control. I called the approach control supervisor. He said he was not aware of any problem at that time, because he was busy with another problem. He said he would look into our problem and for me to call him in 2 days. Without TCASII we would not have known about the other aircraft, and possibly would have hit him.

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Original NASA ASRS Text

Title: L1011 HAS NMAC WITH SECOND ACFT DURING VECTORS TO APCH.

Narrative: ON DOWNWIND TO RWY 22L AT EWR, AT 5000 FT, WE WERE TOLD TO DSND TO 4000 FT. WE STARTED OUR DSCNT AND THE TCASII GAVE US A TA. WE OBSERVED TFC AT 900 FT BELOW US ON TCASII. HE APPEARED TO BE RIGHT UNDER OUR L WING. AT FIRST I THOUGHT HE MAY BE GOING IN THE OPPOSITE DIRECTION BUT HIS POS DID NOT CHANGE, SO I KICKED OFF THE AUTOPLT AND BEGAN TO CLB BACK UP TO 5000 FT. AT THIS TIME THE CTLR ASKED IF WE WERE MAINTAINING 5000 FT. WE ASKED THE CTLR ABOUT THE OTHER ACFT, AND HE SAID THAT IT WAS NOT UNDER HIS CTL. I CALLED THE APCH CTL SUPVR. HE SAID HE WAS NOT AWARE OF ANY PROB AT THAT TIME, BECAUSE HE WAS BUSY WITH ANOTHER PROB. HE SAID HE WOULD LOOK INTO OUR PROB AND FOR ME TO CALL HIM IN 2 DAYS. WITHOUT TCASII WE WOULD NOT HAVE KNOWN ABOUT THE OTHER ACFT, AND POSSIBLY WOULD HAVE HIT HIM.

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.