Narrative:

We (X) were on a vector, 220 degrees, 10-20 mi west of teterboro airport, paralleling the ILS runway 22L final approach course. The controller was very busy. The controller (approach) told us to turn right 120 degree heading. At around 360 degrees we got a TCASII TA. At our 1 O'clock position was traffic (Y) 500 ft above, then 400 ft above, 300 ft above. I disconnected the autoplt, leveled the wings. The captain took the aircraft. I then saw an MD80 (Y) at about my 12:30-1 O'clock position turning to the right slightly. I told the captain turn hard right, at the same time the controller was yelling 'turn left 190 degrees.' we continued our right turn and made a rapid descent. The controller was yelling to descend to 3000 ft immediately. TCASII alert said climb (RA). The MD80 was definitely above us by 100 ft and not descending. Controller was removed from the scope. Normal approach and landing. If we were in actual IFR at time, there would have been a midair. TCASII may not have been accurate due to the 180-270 degree turn. TCASII did not give an adequate TA and gave a wrong RA.

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Original NASA ASRS Text

Title: B737 FLC INITIATES EVASIVE MANEUVER OBSERVING A DSNDING MD80 ABOVE AND ON A CONVERGING FLT PATH WHILE UNDER N90 CTL.

Narrative: WE (X) WERE ON A VECTOR, 220 DEGS, 10-20 MI W OF TETERBORO ARPT, PARALLELING THE ILS RWY 22L FINAL APCH COURSE. THE CTLR WAS VERY BUSY. THE CTLR (APCH) TOLD US TO TURN R 120 DEG HDG. AT AROUND 360 DEGS WE GOT A TCASII TA. AT OUR 1 O'CLOCK POS WAS TFC (Y) 500 FT ABOVE, THEN 400 FT ABOVE, 300 FT ABOVE. I DISCONNECTED THE AUTOPLT, LEVELED THE WINGS. THE CAPT TOOK THE ACFT. I THEN SAW AN MD80 (Y) AT ABOUT MY 12:30-1 O'CLOCK POS TURNING TO THE R SLIGHTLY. I TOLD THE CAPT TURN HARD R, AT THE SAME TIME THE CTLR WAS YELLING 'TURN L 190 DEGS.' WE CONTINUED OUR R TURN AND MADE A RAPID DSCNT. THE CTLR WAS YELLING TO DSND TO 3000 FT IMMEDIATELY. TCASII ALERT SAID CLB (RA). THE MD80 WAS DEFINITELY ABOVE US BY 100 FT AND NOT DSNDING. CTLR WAS REMOVED FROM THE SCOPE. NORMAL APCH AND LNDG. IF WE WERE IN ACTUAL IFR AT TIME, THERE WOULD HAVE BEEN A MIDAIR. TCASII MAY NOT HAVE BEEN ACCURATE DUE TO THE 180-270 DEG TURN. TCASII DID NOT GIVE AN ADEQUATE TA AND GAVE A WRONG RA.

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.