Narrative:

The following TCAS incident occurred on a commercial airline flight into bdl airport in an medium large transport aircraft on which I was serving as first officer. WX conditions were VMC in typical summer haze resulting in reduced visibility. We were on a vector to a left downwind leg, about 20 mi from the airport, and had been told to expect a visual approach once the airport was in sight. Descending through about 7000 ft on a clearance to 6000 (clean confign, 250 KTS IAS, autoplt and autothrottles engaged, I was flying), we received a traffic advisory from the approach controller concerning an aircraft at our 11 O'clock position. The traffic was described not by its type, but by its operator's name, a name neither of us recognized. The captain of our aircraft saw traffic 'a' that position which he took to be the aircraft in question and he advised the controller accordingly. While I did not see the traffic, the captain advised me that as long as it continued on its present heading, it would not be a factor for us. Shortly thereafter, the TCAS advised 'traffic traffic' and displayed a yellow circle at our 11 O'clock position. The TCAS was on the 40 mi range and displayed a large number of targets (well in excess of ten). The yellow target, on this range, appeared very close to our position on the display, sufficiently close to be lost in clutter of other aircraft and essentially uninterpretable, so I selected the 5 mi range for a meaningful look. I anticipated that the target would be the non-conflicting traffic which had been called out and seen by the captain. The captain continued looking out the windshield for the traffic. Before the shorter range display could be fully painted and interpreted, the TCAS gave us a 'climb climb climb' advisory and the perimeter lights on the vsi indicator displayed red from the bottom of the instrument through zero and up to some high positive vertical climb rate, where several green lights were displayed. My earlier expectation that no hazard existed appeared now to have been incorrect and I responded by rolling the autoplt's vertical speed thumb wheel up to a high rate of climb. The autoplt's smooth transition from a 1000 FPM descent to a commanded climb in excess of 2000 FPM was apparently not sufficient for the situation since, in the midst of that vertical speed transition, the TCAS advised 'increase climb increase climb'. I disengaged the autoplt and hand flew the aircraft to a higher nose attitude. During this maneuver (which created a slight bump for the passengers since the pitch trim had not quite kept up with the pitch increase), I saw an opposite direction medium sized twin pass off to our left side and slightly below us. I would judge that separation was less than half a mile... Perhaps a quarter of a mi. As it disappeared from view behind us, the TCAS advised 'clear of conflict'. I gently transitioned from a high climb rate to a comfortable descent and returned to the 6000 ft altitude to which we had been originally cleared. The captain advised the approach controller of the incident and the controller reaffirmed that we were cleared to return to 6000 ft. Upon subsequent telephone conversations with the controller, we learned that the intruding aircraft was a commuter and had been the traffic originally called out to us. The traffic we had seen had been a second target (an medium large transport) which had not been called out. The sudden climb had not, in this instance, compromised separation with any other IFR aircraft.

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Original NASA ASRS Text

Title: TFC ADVISORY GIVEN BUT WRONG TFC SIGHTED. TCASII RA CAUSED FLC TO CLB UNTIL TCASII ANNOUNCED CLR OF TFC.

Narrative: THE FOLLOWING TCAS INCIDENT OCCURRED ON A COMMERCIAL AIRLINE FLT INTO BDL ARPT IN AN MLG ACFT ON WHICH I WAS SERVING AS FO. WX CONDITIONS WERE VMC IN TYPICAL SUMMER HAZE RESULTING IN REDUCED VISIBILITY. WE WERE ON A VECTOR TO A L DOWNWIND LEG, ABOUT 20 MI FROM THE ARPT, AND HAD BEEN TOLD TO EXPECT A VISUAL APCH ONCE THE ARPT WAS IN SIGHT. DSNDING THROUGH ABOUT 7000 FT ON A CLRNC TO 6000 (CLEAN CONFIGN, 250 KTS IAS, AUTOPLT AND AUTOTHROTTLES ENGAGED, I WAS FLYING), WE RECEIVED A TFC ADVISORY FROM THE APCH CTLR CONCERNING AN ACFT AT OUR 11 O'CLOCK POS. THE TFC WAS DESCRIBED NOT BY ITS TYPE, BUT BY ITS OPERATOR'S NAME, A NAME NEITHER OF US RECOGNIZED. THE CAPT OF OUR ACFT SAW TFC 'A' THAT POS WHICH HE TOOK TO BE THE ACFT IN QUESTION AND HE ADVISED THE CTLR ACCORDINGLY. WHILE I DID NOT SEE THE TFC, THE CAPT ADVISED ME THAT AS LONG AS IT CONTINUED ON ITS PRESENT HDG, IT WOULD NOT BE A FACTOR FOR US. SHORTLY THEREAFTER, THE TCAS ADVISED 'TFC TFC' AND DISPLAYED A YELLOW CIRCLE AT OUR 11 O'CLOCK POS. THE TCAS WAS ON THE 40 MI RANGE AND DISPLAYED A LARGE NUMBER OF TARGETS (WELL IN EXCESS OF TEN). THE YELLOW TARGET, ON THIS RANGE, APPEARED VERY CLOSE TO OUR POS ON THE DISPLAY, SUFFICIENTLY CLOSE TO BE LOST IN CLUTTER OF OTHER ACFT AND ESSENTIALLY UNINTERPRETABLE, SO I SELECTED THE 5 MI RANGE FOR A MEANINGFUL LOOK. I ANTICIPATED THAT THE TARGET WOULD BE THE NON-CONFLICTING TFC WHICH HAD BEEN CALLED OUT AND SEEN BY THE CAPT. THE CAPT CONTINUED LOOKING OUT THE WINDSHIELD FOR THE TFC. BEFORE THE SHORTER RANGE DISPLAY COULD BE FULLY PAINTED AND INTERPRETED, THE TCAS GAVE US A 'CLB CLB CLB' ADVISORY AND THE PERIMETER LIGHTS ON THE VSI INDICATOR DISPLAYED RED FROM THE BOTTOM OF THE INST THROUGH ZERO AND UP TO SOME HIGH POSITIVE VERT CLB RATE, WHERE SEVERAL GREEN LIGHTS WERE DISPLAYED. MY EARLIER EXPECTATION THAT NO HAZARD EXISTED APPEARED NOW TO HAVE BEEN INCORRECT AND I RESPONDED BY ROLLING THE AUTOPLT'S VERT SPD THUMB WHEEL UP TO A HIGH RATE OF CLB. THE AUTOPLT'S SMOOTH TRANSITION FROM A 1000 FPM DSCNT TO A COMMANDED CLB IN EXCESS OF 2000 FPM WAS APPARENTLY NOT SUFFICIENT FOR THE SITUATION SINCE, IN THE MIDST OF THAT VERT SPD TRANSITION, THE TCAS ADVISED 'INCREASE CLB INCREASE CLB'. I DISENGAGED THE AUTOPLT AND HAND FLEW THE ACFT TO A HIGHER NOSE ATTITUDE. DURING THIS MANEUVER (WHICH CREATED A SLIGHT BUMP FOR THE PAXS SINCE THE PITCH TRIM HAD NOT QUITE KEPT UP WITH THE PITCH INCREASE), I SAW AN OPPOSITE DIRECTION MEDIUM SIZED TWIN PASS OFF TO OUR L SIDE AND SLIGHTLY BELOW US. I WOULD JUDGE THAT SEPARATION WAS LESS THAN HALF A MILE... PERHAPS A QUARTER OF A MI. AS IT DISAPPEARED FROM VIEW BEHIND US, THE TCAS ADVISED 'CLR OF CONFLICT'. I GENTLY TRANSITIONED FROM A HIGH CLB RATE TO A COMFORTABLE DSCNT AND RETURNED TO THE 6000 FT ALT TO WHICH WE HAD BEEN ORIGINALLY CLRED. THE CAPT ADVISED THE APCH CTLR OF THE INCIDENT AND THE CTLR REAFFIRMED THAT WE WERE CLRED TO RETURN TO 6000 FT. UPON SUBSEQUENT TELEPHONE CONVERSATIONS WITH THE CTLR, WE LEARNED THAT THE INTRUDING ACFT WAS A COMMUTER AND HAD BEEN THE TFC ORIGINALLY CALLED OUT TO US. THE TFC WE HAD SEEN HAD BEEN A SECOND TARGET (AN MLG) WHICH HAD NOT BEEN CALLED OUT. THE SUDDEN CLB HAD NOT, IN THIS INSTANCE, COMPROMISED SEPARATION WITH ANY OTHER IFR ACFT.

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.