Narrative:

I was in level cruise flight at approximately 3800 ft MSL (500+ ft below the ceiling), about 10 NM north of pdk heading west. Knowing that pdk is a busy class D airport with a considerable amount of jet and turbojet traffic, I was focusing most of my traffic scan on my left side of my aircraft looking for any departure traffic. As I glanced to my right to check for traffic, a twin engine aircraft dropped through IMC and crossed my flight path. The twin crossed my flight path at a distance that I estimated approximately 500 ft ahead of, and 250 ft above, my altitude. No evasive actions were required on my part, although I probably made an instinctive tug to the right on the yoke. The twin, after clearing my flight path, corrected slightly to the left. I could not tell if this was a response to a prior evasive turn that I did not see, or if it was simply the twin aligning with the runway once in VMC. I did not feel that either aircraft was in immediate danger. However, there was the potential for an incident had the twin dropped through the clouds closer to my aircraft. It certainly had the potential to be a closer call. Contributing to this potential near midair collision was the focus of my traffic scan for departure traffic from the near airport. I perceived (incorrectly) that this was where any traffic would be coming from. Also contributing to this episode was the separation distance from the cloud bases. Although I was maintaining a greater than minimum separation, had I made additional allowances in the vicinity of the busy airport, I would have had a greater cushion to spot traffic. A third contributing factor was my low flight hours in the aircraft type and low flight time in the past 90 days. If nothing else, more time in type and more flight time would allow a greater comfort factor when navigating near high traffic areas. From this potential near midair collision, I learned that I should never assume that I know where traffic will be coming from. Also, I learned that in high traffic areas, I should allow much more than the minimum required cloud separation. Finally, I learned that I should be more vigilant with scanning for traffic, especially when flying aircraft in which I have less familiarity.

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Original NASA ASRS Text

Title: MAINTAINING MINIMUM CLOUD CLRNC BELOW THE CEILING WHILE STAYING CLR OF THE PDK CLASS D, A PA28 PLT NOTES A TWIN ENG ACFT DSND OUT OF THE CLOUDS 500 FT AHEAD AND PROCEEDING TOWARD THE ARPT.

Narrative: I WAS IN LEVEL CRUISE FLT AT APPROX 3800 FT MSL (500+ FT BELOW THE CEILING), ABOUT 10 NM N OF PDK HDG W. KNOWING THAT PDK IS A BUSY CLASS D ARPT WITH A CONSIDERABLE AMOUNT OF JET AND TURBOJET TFC, I WAS FOCUSING MOST OF MY TFC SCAN ON MY L SIDE OF MY ACFT LOOKING FOR ANY DEP TFC. AS I GLANCED TO MY R TO CHK FOR TFC, A TWIN ENG ACFT DROPPED THROUGH IMC AND CROSSED MY FLT PATH. THE TWIN CROSSED MY FLT PATH AT A DISTANCE THAT I ESTIMATED APPROX 500 FT AHEAD OF, AND 250 FT ABOVE, MY ALT. NO EVASIVE ACTIONS WERE REQUIRED ON MY PART, ALTHOUGH I PROBABLY MADE AN INSTINCTIVE TUG TO THE R ON THE YOKE. THE TWIN, AFTER CLRING MY FLT PATH, CORRECTED SLIGHTLY TO THE L. I COULD NOT TELL IF THIS WAS A RESPONSE TO A PRIOR EVASIVE TURN THAT I DID NOT SEE, OR IF IT WAS SIMPLY THE TWIN ALIGNING WITH THE RWY ONCE IN VMC. I DID NOT FEEL THAT EITHER ACFT WAS IN IMMEDIATE DANGER. HOWEVER, THERE WAS THE POTENTIAL FOR AN INCIDENT HAD THE TWIN DROPPED THROUGH THE CLOUDS CLOSER TO MY ACFT. IT CERTAINLY HAD THE POTENTIAL TO BE A CLOSER CALL. CONTRIBUTING TO THIS POTENTIAL NMAC WAS THE FOCUS OF MY TFC SCAN FOR DEP TFC FROM THE NEAR ARPT. I PERCEIVED (INCORRECTLY) THAT THIS WAS WHERE ANY TFC WOULD BE COMING FROM. ALSO CONTRIBUTING TO THIS EPISODE WAS THE SEPARATION DISTANCE FROM THE CLOUD BASES. ALTHOUGH I WAS MAINTAINING A GREATER THAN MINIMUM SEPARATION, HAD I MADE ADDITIONAL ALLOWANCES IN THE VICINITY OF THE BUSY ARPT, I WOULD HAVE HAD A GREATER CUSHION TO SPOT TFC. A THIRD CONTRIBUTING FACTOR WAS MY LOW FLT HRS IN THE ACFT TYPE AND LOW FLT TIME IN THE PAST 90 DAYS. IF NOTHING ELSE, MORE TIME IN TYPE AND MORE FLT TIME WOULD ALLOW A GREATER COMFORT FACTOR WHEN NAVING NEAR HIGH TFC AREAS. FROM THIS POTENTIAL NMAC, I LEARNED THAT I SHOULD NEVER ASSUME THAT I KNOW WHERE TFC WILL BE COMING FROM. ALSO, I LEARNED THAT IN HIGH TFC AREAS, I SHOULD ALLOW MUCH MORE THAN THE MINIMUM REQUIRED CLOUD SEPARATION. FINALLY, I LEARNED THAT I SHOULD BE MORE VIGILANT WITH SCANNING FOR TFC, ESPECIALLY WHEN FLYING ACFT IN WHICH I HAVE LESS FAMILIARITY.

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.