Narrative:

Shortly after being handed off to asheville approach, we received clearance to descend. Just prior to receiving that clearance we were given a TA by asheville approach stating an aircraft out of 7100 ft would be climbing to 8500 ft and that the traffic was located at approximately our 11 O'clock position at the time. I believe he stated the type of aircraft as some type of single engine but I cannot be sure of that. We advised him we had 'no contact' with the traffic. Approximately 2-3 mins later we were given clearance to descend out of our present altitude down to 7200 ft and given a heading of 150 degrees which was slightly right of our present course. The captain initiated the descent and selected the 150 degree heading as instructed. Out of approximately 8500 ft, our skywatch unit showed traffic slightly to the left of us and at approximately 300 ft below. Before I could query ATC on the traffic, the skywatch unit began to give an audible warning of the traffic. The captain stopped the descent, leveling off at 8100 ft, and turned to the right in an attempt to avoid a collision. We did not have the aircraft in sight at the time and flight conditions were IMC. Our estimate on 'distant missed' is based solely off the skywatch information. Both the captain and I know that a maneuver based solely on the information provided by skywatch is not preferable, but given the knowledge of the other aircraft near our position both of us felt the actions justified. I feel that allowing the other aircraft to climb without us having visual reference to it was a factor in this case. Additionally, I believe the controller may not have known the flight conditions that we were in at the time (we did not state we were in IMC). I believe in this case it would have been appropriate for ATC to delay our descent until the traffic was either in sight or clear of our position/path. Lastly, it would have been helpful if I would have asked for additional information on the traffic's position as we started our descent. Supplemental information from acn 593179: our skywatch unit showed us converging traffic climbing at the 11 O'clock position. Controller asked us why we turned into the VFR traffic. We told controller that we took evasive action.

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Original NASA ASRS Text

Title: AN IFR ACFT DSNDING IN IMC TAKES EVASIVE ACTION BASED ON ITS SKY WATCH UNIT TO AVOID A CLBING VFR ACFT, THAT HAD BEEN RPTED BY THE APCH CTLR, BY AN ESTIMATED 100 FT.

Narrative: SHORTLY AFTER BEING HANDED OFF TO ASHEVILLE APCH, WE RECEIVED CLRNC TO DSND. JUST PRIOR TO RECEIVING THAT CLRNC WE WERE GIVEN A TA BY ASHEVILLE APCH STATING AN ACFT OUT OF 7100 FT WOULD BE CLBING TO 8500 FT AND THAT THE TFC WAS LOCATED AT APPROX OUR 11 O'CLOCK POS AT THE TIME. I BELIEVE HE STATED THE TYPE OF ACFT AS SOME TYPE OF SINGLE ENG BUT I CANNOT BE SURE OF THAT. WE ADVISED HIM WE HAD 'NO CONTACT' WITH THE TFC. APPROX 2-3 MINS LATER WE WERE GIVEN CLRNC TO DSND OUT OF OUR PRESENT ALT DOWN TO 7200 FT AND GIVEN A HDG OF 150 DEGS WHICH WAS SLIGHTLY R OF OUR PRESENT COURSE. THE CAPT INITIATED THE DSCNT AND SELECTED THE 150 DEG HDG AS INSTRUCTED. OUT OF APPROX 8500 FT, OUR SKYWATCH UNIT SHOWED TFC SLIGHTLY TO THE L OF US AND AT APPROX 300 FT BELOW. BEFORE I COULD QUERY ATC ON THE TFC, THE SKYWATCH UNIT BEGAN TO GIVE AN AUDIBLE WARNING OF THE TFC. THE CAPT STOPPED THE DSCNT, LEVELING OFF AT 8100 FT, AND TURNED TO THE R IN AN ATTEMPT TO AVOID A COLLISION. WE DID NOT HAVE THE ACFT IN SIGHT AT THE TIME AND FLT CONDITIONS WERE IMC. OUR ESTIMATE ON 'DISTANT MISSED' IS BASED SOLELY OFF THE SKYWATCH INFO. BOTH THE CAPT AND I KNOW THAT A MANEUVER BASED SOLELY ON THE INFO PROVIDED BY SKYWATCH IS NOT PREFERABLE, BUT GIVEN THE KNOWLEDGE OF THE OTHER ACFT NEAR OUR POS BOTH OF US FELT THE ACTIONS JUSTIFIED. I FEEL THAT ALLOWING THE OTHER ACFT TO CLB WITHOUT US HAVING VISUAL REF TO IT WAS A FACTOR IN THIS CASE. ADDITIONALLY, I BELIEVE THE CTLR MAY NOT HAVE KNOWN THE FLT CONDITIONS THAT WE WERE IN AT THE TIME (WE DID NOT STATE WE WERE IN IMC). I BELIEVE IN THIS CASE IT WOULD HAVE BEEN APPROPRIATE FOR ATC TO DELAY OUR DSCNT UNTIL THE TFC WAS EITHER IN SIGHT OR CLR OF OUR POS/PATH. LASTLY, IT WOULD HAVE BEEN HELPFUL IF I WOULD HAVE ASKED FOR ADDITIONAL INFO ON THE TFC'S POS AS WE STARTED OUR DSCNT. SUPPLEMENTAL INFO FROM ACN 593179: OUR SKYWATCH UNIT SHOWED US CONVERGING TFC CLBING AT THE 11 O'CLOCK POS. CTLR ASKED US WHY WE TURNED INTO THE VFR TFC. WE TOLD CTLR THAT WE TOOK EVASIVE ACTION.

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.