Narrative:

Descending through 11000 ft we saw another aircraft slightly above us, ahead and to our right. At first I thought it was a large aircraft, opposite direction, 2-5 mi away, and 1000 ft or more above. However, about 2-3 seconds later we passed the aircraft and realized it was a white single engine cessna, about 1/4 mi away or less. It appeared to be level at about 11000 ft and sbound, as we were. We had descended a few hundred ft below it when it passed off our right wing. By the time we recognized our proximity to that aircraft, there was no time to take any evasive action, and fortunately no need. We had received no TA from daytona approach control, and our TCASII system was inoperative (as it had been for several days). When queried, approach said they had no traffic (transponder equipped, primary target, or other) at that location but they did have another aircraft still ahead of us at 3000 ft. The WX was clear at 11000 ft with 5-10 mi horizontal visibility in haze, with broken cumulus clouds below (tops about 3000 ft) and high twring cumulus ahead, south of us. It was not possible to see the white aircraft against that backgnd as we descended directly toward him, and we only saw him when he began moving in our windscreen, very few seconds before we passed him. This situation illustrates the failure of the see and avoid concept to insure aircraft separation. I believe a midair collision was avoided by chance.

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Original NASA ASRS Text

Title: AIRBORNE CONFLICT BTWN AN MLG ON DSCNT INTO A TERMINAL AREA AND AN SMA SEL ON A SIMILAR ALT AND DIRECTION.

Narrative: DSNDING THROUGH 11000 FT WE SAW ANOTHER ACFT SLIGHTLY ABOVE US, AHEAD AND TO OUR R. AT FIRST I THOUGHT IT WAS A LARGE ACFT, OPPOSITE DIRECTION, 2-5 MI AWAY, AND 1000 FT OR MORE ABOVE. HOWEVER, ABOUT 2-3 SECONDS LATER WE PASSED THE ACFT AND REALIZED IT WAS A WHITE SINGLE ENG CESSNA, ABOUT 1/4 MI AWAY OR LESS. IT APPEARED TO BE LEVEL AT ABOUT 11000 FT AND SBOUND, AS WE WERE. WE HAD DSNDED A FEW HUNDRED FT BELOW IT WHEN IT PASSED OFF OUR R WING. BY THE TIME WE RECOGNIZED OUR PROX TO THAT ACFT, THERE WAS NO TIME TO TAKE ANY EVASIVE ACTION, AND FORTUNATELY NO NEED. WE HAD RECEIVED NO TA FROM DAYTONA APCH CTL, AND OUR TCASII SYS WAS INOP (AS IT HAD BEEN FOR SEVERAL DAYS). WHEN QUERIED, APCH SAID THEY HAD NO TFC (XPONDER EQUIPPED, PRIMARY TARGET, OR OTHER) AT THAT LOCATION BUT THEY DID HAVE ANOTHER ACFT STILL AHEAD OF US AT 3000 FT. THE WX WAS CLR AT 11000 FT WITH 5-10 MI HORIZ VISIBILITY IN HAZE, WITH BROKEN CUMULUS CLOUDS BELOW (TOPS ABOUT 3000 FT) AND HIGH TWRING CUMULUS AHEAD, S OF US. IT WAS NOT POSSIBLE TO SEE THE WHITE ACFT AGAINST THAT BACKGND AS WE DSNDED DIRECTLY TOWARD HIM, AND WE ONLY SAW HIM WHEN HE BEGAN MOVING IN OUR WINDSCREEN, VERY FEW SECONDS BEFORE WE PASSED HIM. THIS SIT ILLUSTRATES THE FAILURE OF THE SEE AND AVOID CONCEPT TO INSURE ACFT SEPARATION. I BELIEVE A MIDAIR COLLISION WAS AVOIDED BY CHANCE.

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.