Narrative:

Flight departed runway 34 at bgm. After departure we were given a left turn to 180 degrees direct avp when able. Upon rolling out on 180 degree heading, we received a TA by TCASII for traffic at 11 O'clock and 1300 ft below our altitude. The TA then became a 'descend, crossing descend' RA approximately 5 seconds later. I, the captain, was flying and initiated the commanded 1500 FPM descent. When the RA was initially received we were at 3400 MSL and approximately 2000 ft AGL. Once established in the descent the RA became a blue proximity target at 10 O'clock and 1200 ft below our altitude. The target then moved rapidly off to our left rear and disappeared from TCASII. A normal climb was resumed and ATC was advised. ATC stated the only traffic they had was a departure off runway 34 at bgm and was approximately 5 mi at our 7 O'clock position. I believe that the RA was in response to the aircraft departing bgm runway 34 which was an aircraft which has a rapid climb rate. Our aircraft was just rolling out of a 20 degree left bank which may have contributed to the large azimuth error on TCASII. The TCASII system installed in our aircraft often displays rapid azimuth changes.

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Original NASA ASRS Text

Title: LTT ACR HAS TCASII RA DURING CLB. RESPONDS.

Narrative: FLT DEPARTED RWY 34 AT BGM. AFTER DEP WE WERE GIVEN A L TURN TO 180 DEGS DIRECT AVP WHEN ABLE. UPON ROLLING OUT ON 180 DEG HDG, WE RECEIVED A TA BY TCASII FOR TFC AT 11 O'CLOCK AND 1300 FT BELOW OUR ALT. THE TA THEN BECAME A 'DSND, XING DSND' RA APPROX 5 SECONDS LATER. I, THE CAPT, WAS FLYING AND INITIATED THE COMMANDED 1500 FPM DSCNT. WHEN THE RA WAS INITIALLY RECEIVED WE WERE AT 3400 MSL AND APPROX 2000 FT AGL. ONCE ESTABLISHED IN THE DSCNT THE RA BECAME A BLUE PROX TARGET AT 10 O'CLOCK AND 1200 FT BELOW OUR ALT. THE TARGET THEN MOVED RAPIDLY OFF TO OUR L REAR AND DISAPPEARED FROM TCASII. A NORMAL CLB WAS RESUMED AND ATC WAS ADVISED. ATC STATED THE ONLY TFC THEY HAD WAS A DEP OFF RWY 34 AT BGM AND WAS APPROX 5 MI AT OUR 7 O'CLOCK POS. I BELIEVE THAT THE RA WAS IN RESPONSE TO THE ACFT DEPARTING BGM RWY 34 WHICH WAS AN ACFT WHICH HAS A RAPID CLB RATE. OUR ACFT WAS JUST ROLLING OUT OF A 20 DEG L BANK WHICH MAY HAVE CONTRIBUTED TO THE LARGE AZIMUTH ERROR ON TCASII. THE TCASII SYS INSTALLED IN OUR ACFT OFTEN DISPLAYS RAPID AZIMUTH CHANGES.

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.