An air carrier flight crew flying a B737 near isp reports a TCASII RA and near midair collision.

Attributes
ACN	487250
Time
Date	200009
Day	Fri
Local Time Of Day	0601 To 1200
Place
State Reference	NY
Altitude	msl single value : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : o90.tracon
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 06
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 150 flight time total : 14000 flight time type : 5500
ASRS Report	487250
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne critical
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 6000 vertical : 100
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

While being vectored to runway 6 at isp at 3000 ft, we encountered a TCASII RA approximately 1 mi and 12 O'clock to our position. The other aircraft was showing 100 ft below our altitude at the time of the TCASII RA. We immediately initiated a climb. New york approach was advised of our altitude deviation. We landed at isp without further incident. I contacted new york TRACON by phone and spoke to a supervisor. After speaking to the controller that worked our flight the supervisor indicated 'unknown' traffic had 'popped up' at 2700 ft which caused our TCASII RA.

Original NASA ASRS Text

Title: AN ACR FLC FLYING A B737 NEAR ISP RPTS A TCASII RA AND NMAC.

Narrative: WHILE BEING VECTORED TO RWY 6 AT ISP AT 3000 FT, WE ENCOUNTERED A TCASII RA APPROX 1 MI AND 12 O'CLOCK TO OUR POS. THE OTHER ACFT WAS SHOWING 100 FT BELOW OUR ALT AT THE TIME OF THE TCASII RA. WE IMMEDIATELY INITIATED A CLB. NEW YORK APCH WAS ADVISED OF OUR ALTDEV. WE LANDED AT ISP WITHOUT FURTHER INCIDENT. I CONTACTED NEW YORK TRACON BY PHONE AND SPOKE TO A SUPVR. AFTER SPEAKING TO THE CTLR THAT WORKED OUR FLT THE SUPVR INDICATED 'UNKNOWN' TFC HAD 'POPPED UP' AT 2700 FT WHICH CAUSED OUR TCASII 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.