Narrative:

I was the first officer and pilot monitoring. We departed on time and had an uneventful fight until we were in the approach phase of flight. We were on the arrival and transitioning to vectors. ATC had given us vectors for a right downwind for a visual to runway 34 at hpn. We had previously loaded the sound visual at hpn into the FMS; and even though we were not cleared for this approach; and were on vectors the fixes provided some situational awareness. We were level at 3000 ft somewhere between the haarp and shipn when the TCAS announced 'traffic; traffic' and a yellow target appeared at approximately our 2 o'clock and indicating -02 (200 ft below) the captain queried if I saw the traffic. I responded that I did not. The TCAS then issued an RA to descend. The green arc on the vsi was in the decent portion of the vsi. The captain disconnected the autopilot and began a descent. I made a radio call that we were descending in accordance with an RA; no response was received from ATC. At this point the TCAS alerted us again and issued the 'climb; climb now' warning; the green arc was now at the very top of the vsi that can be seen on the display. The captain reversed the trend; and started to climb. I don't remember the exact verbiage but the TCAS instructed a faster climb. I was looking for the traffic; and at this point spotted it to our right flying in the opposite direction and slightly into our flight path. As we passed the traffic I would estimate that it was at our altitude; and approximately 100-200 ft off our right wingtip; about as far away as you would expect an aircraft on a taxiway next to you; while still on the same ramp; to be. I told the captain that the traffic would clear us. At this point we returned to our assigned altitude. We did not change heading throughout the event. I was listening to ATC to try to explain our actions when a break in talking came. I heard the controller arguing with another aircraft in regards to whether or not a readback had been completed. I then notified the controller that we had been climbing and descending due to an RA and that we missed a light twin by about 200 ft. The controller's response was 'sorry about that.' he then handed us off to another controller. We were subsequently cleared down to 2000 feet; but I do not remember if this was the same controller or another; I do recall getting traffic warnings from controllers on several other light general aviation aircraft in the area. It did not appear as if the conflicting traffic was under ATC's control. ATC did not give us a traffic warning. We were in a busy phase of flight; and therefore did not notice the traffic until the first aural warning. The conflicting traffic obviously did not see us. The lack of attention of all 3 parties to traffic contributed to this event.

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Original NASA ASRS Text

Title: A CRJ-200 flight crew experienced an NMAC with a light twin on descent into HPN.

Narrative: I was the First Officer and pilot monitoring. We departed on time and had an uneventful fight until we were in the approach phase of flight. We were on the arrival and transitioning to vectors. ATC had given us vectors for a right downwind for a visual to Runway 34 at HPN. We had previously loaded the Sound Visual at HPN into the FMS; and even though we were not cleared for this approach; and were on vectors the fixes provided some situational awareness. We were level at 3000 FT somewhere between the HAARP and SHIPN when the TCAS announced 'Traffic; Traffic' and a yellow target appeared at approximately our 2 o'clock and indicating -02 (200 FT below) the Captain queried if I saw the traffic. I responded that I did not. The TCAS Then issued an RA to descend. The green arc on the VSI was in the decent portion of the VSI. The Captain disconnected the autopilot and began a descent. I made a radio call that we were descending in accordance with an RA; no response was received from ATC. At this point the TCAS alerted us again and issued the 'Climb; Climb now' warning; the green arc was now at the very top of the VSI that can be seen on the display. The Captain reversed the trend; and started to climb. I don't remember the exact verbiage but the TCAS instructed a faster climb. I was looking for the traffic; and at this point spotted it to our right flying in the opposite direction and slightly into our flight path. As we passed the traffic I would estimate that it was at our altitude; and approximately 100-200 FT off our right wingtip; about as far away as you would expect an aircraft on a taxiway next to you; while still on the same ramp; to be. I told the Captain that the traffic would clear us. At this point we returned to our assigned altitude. We did not change heading throughout the event. I was listening to ATC to try to explain our actions when a break in talking came. I heard the Controller arguing with another aircraft in regards to whether or not a readback had been completed. I then notified the Controller that we had been climbing and descending due to an RA and that we missed a light twin by about 200 FT. The controller's response was 'Sorry about that.' He then handed us off to another controller. We were subsequently cleared down to 2000 feet; but I do not remember if this was the same controller or another; I do recall getting traffic warnings from controllers on several other light general aviation aircraft in the area. It did not appear as if the conflicting traffic was under ATC's control. ATC did not give us a traffic warning. We were in a busy phase of flight; and therefore did not notice the traffic until the first aural warning. The conflicting traffic obviously did not see us. The lack of attention of all 3 parties to traffic contributed to this event.

Data retrieved from NASA's ASRS site as of April 2012 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.