Narrative:

At 2000 ft in cruise flight approximately 12 NM prior to the hto VOR, I observed an aircraft on the skywatch traffic system descending to my altitude. I switched to the 2 NM range and observed no bearing change relative to my aircraft. At 1 1/2 NM and 200 ft vertical separation I queried new york approach control (132.25) as to the intentions of the 'challenger.' ATC told the challenger n-number to immediately climb. At 1/2 NM and 100 ft separation on skywatch, I initiated emergency evasive descent maneuver to 1500 ft MSL and observed the challenger come from behind a cloud directly overhead. I then notified ATC that I had deviated from my cleared altitude and was climbing back to 2000 ft. The approach and landing was uneventful. Supplemental information from acn 518975: TCASII showed him within 100 ft vertically and less than 2 mi -- the last time I looked at the instrument. The only way we avoided the collision was our captain shoved the nose over and we descended 500 ft.

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Original NASA ASRS Text

Title: CAPT OF A BEECH 300 TOOK EVASIVE ACTION AND DSNDED IN RESPONSE TO A TCASII OF ANOTHER ACFT DSNDING AND OVERTAKING HIS ACFT.

Narrative: AT 2000 FT IN CRUISE FLT APPROX 12 NM PRIOR TO THE HTO VOR, I OBSERVED AN ACFT ON THE SKYWATCH TFC SYS DSNDING TO MY ALT. I SWITCHED TO THE 2 NM RANGE AND OBSERVED NO BEARING CHANGE RELATIVE TO MY ACFT. AT 1 1/2 NM AND 200 FT VERT SEPARATION I QUERIED NEW YORK APCH CTL (132.25) AS TO THE INTENTIONS OF THE 'CHALLENGER.' ATC TOLD THE CHALLENGER N-NUMBER TO IMMEDIATELY CLB. AT 1/2 NM AND 100 FT SEPARATION ON SKYWATCH, I INITIATED EMER EVASIVE DSCNT MANEUVER TO 1500 FT MSL AND OBSERVED THE CHALLENGER COME FROM BEHIND A CLOUD DIRECTLY OVERHEAD. I THEN NOTIFIED ATC THAT I HAD DEVIATED FROM MY CLRED ALT AND WAS CLBING BACK TO 2000 FT. THE APCH AND LNDG WAS UNEVENTFUL. SUPPLEMENTAL INFO FROM ACN 518975: TCASII SHOWED HIM WITHIN 100 FT VERTLY AND LESS THAN 2 MI -- THE LAST TIME I LOOKED AT THE INST. THE ONLY WAY WE AVOIDED THE COLLISION WAS OUR CAPT SHOVED THE NOSE OVER AND WE DSNDED 500 FT.

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.