Narrative:

While being vectored for an ILS to runway 6 at isp, we were cleared by approach to descend from 4000 ft to 2000 ft. While descending through 3000 ft, the controller advised us to stop the descent at 3000 ft because an unidented target had popped up at our 12 O'clock position, range 2 mi, 300 ft below us and climbing. The radio transmission was very hard to understand (scratchy bad transmitter) and the first officer who was the PF did not hear the transmission and continued descending through 3000 ft to 2700 ft. I told him to climb back to 3000 ft. At that time the TCASII displayed the traffic at our 12 O'clock position, 1 mi, 200 ft below us. It gave us an RA climb command and the first officer immediately climbed the aircraft to follow the TCASII command at approximately 4000 FPM. We leveled the aircraft at 4000 ft MSL. The first officer saw the light single pass below us at approximately 100 ft below and 400 ft to our right.

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Original NASA ASRS Text

Title: DURING DSCNT INTO ISP, APCH CTLR LEVELS ACR BECAUSE OF UNIDENTED TFC OBSERVED AHEAD.

Narrative: WHILE BEING VECTORED FOR AN ILS TO RWY 6 AT ISP, WE WERE CLRED BY APCH TO DSND FROM 4000 FT TO 2000 FT. WHILE DSNDING THROUGH 3000 FT, THE CTLR ADVISED US TO STOP THE DSCNT AT 3000 FT BECAUSE AN UNIDENTED TARGET HAD POPPED UP AT OUR 12 O'CLOCK POS, RANGE 2 MI, 300 FT BELOW US AND CLBING. THE RADIO XMISSION WAS VERY HARD TO UNDERSTAND (SCRATCHY BAD XMITTER) AND THE FO WHO WAS THE PF DID NOT HEAR THE XMISSION AND CONTINUED DSNDING THROUGH 3000 FT TO 2700 FT. I TOLD HIM TO CLB BACK TO 3000 FT. AT THAT TIME THE TCASII DISPLAYED THE TFC AT OUR 12 O'CLOCK POS, 1 MI, 200 FT BELOW US. IT GAVE US AN RA CLB COMMAND AND THE FO IMMEDIATELY CLBED THE ACFT TO FOLLOW THE TCASII COMMAND AT APPROX 4000 FPM. WE LEVELED THE ACFT AT 4000 FT MSL. THE FO SAW THE LIGHT SINGLE PASS BELOW US AT APPROX 100 FT BELOW AND 400 FT TO OUR R.

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.