Narrative:

Our initial clearance from sdf was to maintain 5000 ft and expect 9000 ft 10 mins after departure. Department control (sdf) cleared us to 10000 ft and gave us a 360 degree heading to intercept V47 west of cvg. While cruising at 10000 ft we were given 'traffic at 10 O'clock 10500 ft climbing back to 11000 ft.' we were in and out of clouds at the time. I, the PF, spotted the traffic a few seconds later. It was initially difficult to tell what the second aircraft, a light twin, was doing. I then realized that the twin was descending and on a near collision course with us. The aircraft passed approximately 200 ft below and 200 ft behind us. I transmitted to departure control that the aircraft was not climbing but descending. The controller did not respond. A few seconds later, the controller cleared us to 9000 ft. Again nothing further was said by departure control or the other aircraft. A few mins later, departure control cleared us back to 10000 ft and handed us off to cvg approach. I strongly suspect the second aircraft was trying to maintain VFR in MVFR conditions as well as the possibility of controller error. The installation of TCASII may have aided in preventing a near disaster.

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Original NASA ASRS Text

Title: NMAC. ATC PROVIDED TFC INFO, BUT STATING THAT TFC WAS CLBING OUT OF 10500 FT FOR 11000 FT. RPTR ACFT, AT 10000 FT, ACQUIRED TFC VISUALLY AND SAW THAT IT WAS DSNDING THROUGH THEIR ALT. DEP CTLR DIDN'T RESPOND TO RPTR XMISSION REGARDING TFC.

Narrative: OUR INITIAL CLRNC FROM SDF WAS TO MAINTAIN 5000 FT AND EXPECT 9000 FT 10 MINS AFTER DEP. DEPT CTL (SDF) CLRED US TO 10000 FT AND GAVE US A 360 DEG HDG TO INTERCEPT V47 W OF CVG. WHILE CRUISING AT 10000 FT WE WERE GIVEN 'TFC AT 10 O'CLOCK 10500 FT CLBING BACK TO 11000 FT.' WE WERE IN AND OUT OF CLOUDS AT THE TIME. I, THE PF, SPOTTED THE TFC A FEW SECONDS LATER. IT WAS INITIALLY DIFFICULT TO TELL WHAT THE SECOND ACFT, A LIGHT TWIN, WAS DOING. I THEN REALIZED THAT THE TWIN WAS DSNDING AND ON A NEAR COLLISION COURSE WITH US. THE ACFT PASSED APPROX 200 FT BELOW AND 200 FT BEHIND US. I XMITTED TO DEP CTL THAT THE ACFT WAS NOT CLBING BUT DSNDING. THE CTLR DID NOT RESPOND. A FEW SECONDS LATER, THE CTLR CLRED US TO 9000 FT. AGAIN NOTHING FURTHER WAS SAID BY DEP CTL OR THE OTHER ACFT. A FEW MINS LATER, DEP CTL CLRED US BACK TO 10000 FT AND HANDED US OFF TO CVG APCH. I STRONGLY SUSPECT THE SECOND ACFT WAS TRYING TO MAINTAIN VFR IN MVFR CONDITIONS AS WELL AS THE POSSIBILITY OF CTLR ERROR. THE INSTALLATION OF TCASII MAY HAVE AIDED IN PREVENTING A NEAR DISASTER.

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.