Narrative:

We were inbound to our home airport, 15 mi out, when center called unidented traffic, 12 O'clock, 2 mi, same direction, 1500 ft below our altitude. It was a perfectly clear night, but neither my passenger nor me could find the target. There were many ground lights ahead that may have obscured the other aircraft's lights. Shortly, I started to descend, and center reported radar contact lost. As we switched to the local advisory frequency, my passenger reported that another aircraft going the 'opposite direction' had just passed beneath our right wing. I never saw the other aircraft. Almost immediately, a C172 from one of the local flight schools reported inbound on the CTAF from a position very close to our own. I then realized that we had overtaken and passed the 'unidented' target and that our much higher speed had made my passenger think we were going in opposite directions. Though we were both looking out at all times, it was only luck that prevented a collision. There are at least 3 things that could have reduced the danger of this situation. 1) I should have realized that the traffic ahead may have been slower. If I had changed course by 30 degrees for a few mi before turning in toward the airport, I would have avoided coming up rapidly behind traffic I couldn't see. 2) if center controllers had noted that we were rapidly overtaking the traffic ahead, I would not have descended before locating it. They gave us no information about our relative ground speeds. 3) the single white tail light on many small GA aircraft is virtually useless to trailing aircraft when descending toward a brightly lit city. I don't know if the other aircraft was operating a beacon light, but I suspect that better anti-collision lighting (strobes) would have allowed us to spot the other plane and avoid the close encounter.

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Original NASA ASRS Text

Title: SMA PLT HAD NMAC WITH C172 IN ZSE CLASS E AIRSPACE.

Narrative: WE WERE INBOUND TO OUR HOME ARPT, 15 MI OUT, WHEN CTR CALLED UNIDENTED TFC, 12 O'CLOCK, 2 MI, SAME DIRECTION, 1500 FT BELOW OUR ALT. IT WAS A PERFECTLY CLR NIGHT, BUT NEITHER MY PAX NOR ME COULD FIND THE TARGET. THERE WERE MANY GND LIGHTS AHEAD THAT MAY HAVE OBSCURED THE OTHER ACFT'S LIGHTS. SHORTLY, I STARTED TO DSND, AND CTR RPTED RADAR CONTACT LOST. AS WE SWITCHED TO THE LCL ADVISORY FREQ, MY PAX RPTED THAT ANOTHER ACFT GOING THE 'OPPOSITE DIRECTION' HAD JUST PASSED BENEATH OUR R WING. I NEVER SAW THE OTHER ACFT. ALMOST IMMEDIATELY, A C172 FROM ONE OF THE LCL FLT SCHOOLS RPTED INBOUND ON THE CTAF FROM A POS VERY CLOSE TO OUR OWN. I THEN REALIZED THAT WE HAD OVERTAKEN AND PASSED THE 'UNIDENTED' TARGET AND THAT OUR MUCH HIGHER SPD HAD MADE MY PAX THINK WE WERE GOING IN OPPOSITE DIRECTIONS. THOUGH WE WERE BOTH LOOKING OUT AT ALL TIMES, IT WAS ONLY LUCK THAT PREVENTED A COLLISION. THERE ARE AT LEAST 3 THINGS THAT COULD HAVE REDUCED THE DANGER OF THIS SIT. 1) I SHOULD HAVE REALIZED THAT THE TFC AHEAD MAY HAVE BEEN SLOWER. IF I HAD CHANGED COURSE BY 30 DEGS FOR A FEW MI BEFORE TURNING IN TOWARD THE ARPT, I WOULD HAVE AVOIDED COMING UP RAPIDLY BEHIND TFC I COULDN'T SEE. 2) IF CTR CTLRS HAD NOTED THAT WE WERE RAPIDLY OVERTAKING THE TFC AHEAD, I WOULD NOT HAVE DSNDED BEFORE LOCATING IT. THEY GAVE US NO INFO ABOUT OUR RELATIVE GND SPDS. 3) THE SINGLE WHITE TAIL LIGHT ON MANY SMALL GA ACFT IS VIRTUALLY USELESS TO TRAILING ACFT WHEN DSNDING TOWARD A BRIGHTLY LIT CITY. I DON'T KNOW IF THE OTHER ACFT WAS OPERATING A BEACON LIGHT, BUT I SUSPECT THAT BETTER ANTI-COLLISION LIGHTING (STROBES) WOULD HAVE ALLOWED US TO SPOT THE OTHER PLANE AND AVOID THE CLOSE ENCOUNTER.

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.