Narrative:

While on vectors from ATC, crew spotted an aircraft (small propeller commuter) at 10 O'clock position, about 5 mi. Subject aircraft appeared to be at our altitude, constant bearing, decreasing range. TCASII indications agreed. Crew attempted to contact ZNY about the aircraft but due to the amount of xmissions were unable. Crew then received a TCASII TA followed by an RA calling for a 3000 FPM descent. As crew descended through 4600 ft we observed subject aircraft pass directly overhead, about 400 ft above us. When we got through to ZNY we advised them of our TCASII alert and descent to 4300 ft. We were told by ATC to climb back to 5000 ft. We were also told subject aircraft had us visually. At no time did we observe the subject aircraft to take any evasive action. ATC was too busy doing 'normal' controling, had no time for unusual sits. Subject aircraft was in the same area and at same altitude, yet on a different frequency than we were on. If indeed the other aircraft was to remain clear of us visually, in a high density area, that aircraft must be certain who it is to be watching. If we would have been IMC without TCASII this may well have been a midair situation.

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Original NASA ASRS Text

Title: LGT HAS NMAC WITH COMMUTER WHILE ON VECTORS.

Narrative: WHILE ON VECTORS FROM ATC, CREW SPOTTED AN ACFT (SMALL PROP COMMUTER) AT 10 O'CLOCK POS, ABOUT 5 MI. SUBJECT ACFT APPEARED TO BE AT OUR ALT, CONSTANT BEARING, DECREASING RANGE. TCASII INDICATIONS AGREED. CREW ATTEMPTED TO CONTACT ZNY ABOUT THE ACFT BUT DUE TO THE AMOUNT OF XMISSIONS WERE UNABLE. CREW THEN RECEIVED A TCASII TA FOLLOWED BY AN RA CALLING FOR A 3000 FPM DSCNT. AS CREW DSNDED THROUGH 4600 FT WE OBSERVED SUBJECT ACFT PASS DIRECTLY OVERHEAD, ABOUT 400 FT ABOVE US. WHEN WE GOT THROUGH TO ZNY WE ADVISED THEM OF OUR TCASII ALERT AND DSCNT TO 4300 FT. WE WERE TOLD BY ATC TO CLB BACK TO 5000 FT. WE WERE ALSO TOLD SUBJECT ACFT HAD US VISUALLY. AT NO TIME DID WE OBSERVE THE SUBJECT ACFT TO TAKE ANY EVASIVE ACTION. ATC WAS TOO BUSY DOING 'NORMAL' CTLING, HAD NO TIME FOR UNUSUAL SITS. SUBJECT ACFT WAS IN THE SAME AREA AND AT SAME ALT, YET ON A DIFFERENT FREQ THAN WE WERE ON. IF INDEED THE OTHER ACFT WAS TO REMAIN CLR OF US VISUALLY, IN A HIGH DENSITY AREA, THAT ACFT MUST BE CERTAIN WHO IT IS TO BE WATCHING. IF WE WOULD HAVE BEEN IMC WITHOUT TCASII THIS MAY WELL HAVE BEEN A MIDAIR SIT.

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.