Narrative:

We had descended through an overcast to 4000 ft MSL into VMC conditions. We called the runway in sight from about 8 mi out and were cleared for a visual approach, straight in, to runway 6 at abe airport. At about 7 mi out, approach called traffic off to our left at 1500 ft on a 090 degree heading (converging with us left to right at a 30 degree angle). He also was in radio contact with that aircraft. I told approach I would level at 2000 ft and look for the traffic while I continued our approach. Both pilots in my aircraft took the traffic call very seriously and made every effort to get a visual on it. We made repeated calls to approach for advisories reference the traffic and were repeatedly told he was 11 - 12 O'clock at 1500 ft eastbound. We were now about 3 mi from the runway end, still at 2000 ft MSL (1600 ft AGL), and we either had to start a descent or abandon the approach. We again asked approach where the traffic was. He said the traffic was 1 mi 'dead 12 O'clock.' we continued to search for the traffic and hold 2000 ft. By now I was getting concerned about not being able to get down in time to make the runway. I was also starting to get the feeling that a bad situation was developing. We asked once more for the traffic. I had decided that if we did not see the traffic or get a clear of traffic advisory, I would abandon the approach. Approach replied we were 'right overhead' the traffic and he was 'clearing to our right.' we acknowledged the transmission and told him we were descending out of 2000 ft. He acknowledged that and then told the other aircraft that there was some traffic (us) and that he should turn to the southeast (right). I then busied myself with the task of completing the landing checklist. As I was going through 1500 ft MSL I looked out of my left window and there saw the traffic that we were told had cleared to our right. It was a C150 traffic patrol aircraft. He was very slightly above us and very close laterally. He was also in a right turn towards us. It is difficult to estimate horizontal distance but I was close enough that had I saw a person in the aircraft I would have clearly been able to recognize him (100-200 ft?). After a second or two to assimilate the situation, I pushed the aircraft hard over into a descent to avoid what almost certainly would have been a midair. After I straightened out the aircraft we called the traffic, got switched to tower, cleared and landed. I visited the control tower and we listened to the tape and discussed the incident. It seems the separation standards for class C airspace were not violated. They rptedly are 500 ft vertical and 'green between.' since we did not collide, there was evidently 'green between.' the fact that 2 very experienced and motivated pilots can fail to spot called traffic in virtually unlimited visual conditions until they almost collide, to me, points up the weaknesses in the separation standards for class C airspace and in overdependence on 'see and avoid.'

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Original NASA ASRS Text

Title: CPR LTT ON APCH RWY 6 ABE IS ADVISED OF TFC CONVERGING L TO R. STAYED AT 2000 FT UNTIL TFC SIGHTED. UNABLE TO LOCATE UNTIL 3 MI FROM ARPT. SAW C150 SLIGHTLY ABOVE AND TURNING TOWARD THE ACFT. MADE A RAPID DSCNT TO AVOID AND CLRED TO TWR FOR LNDG.

Narrative: WE HAD DSNDED THROUGH AN OVCST TO 4000 FT MSL INTO VMC CONDITIONS. WE CALLED THE RWY IN SIGHT FROM ABOUT 8 MI OUT AND WERE CLRED FOR A VISUAL APCH, STRAIGHT IN, TO RWY 6 AT ABE ARPT. AT ABOUT 7 MI OUT, APCH CALLED TFC OFF TO OUR L AT 1500 FT ON A 090 DEG HDG (CONVERGING WITH US L TO R AT A 30 DEG ANGLE). HE ALSO WAS IN RADIO CONTACT WITH THAT ACFT. I TOLD APCH I WOULD LEVEL AT 2000 FT AND LOOK FOR THE TFC WHILE I CONTINUED OUR APCH. BOTH PLTS IN MY ACFT TOOK THE TFC CALL VERY SERIOUSLY AND MADE EVERY EFFORT TO GET A VISUAL ON IT. WE MADE REPEATED CALLS TO APCH FOR ADVISORIES REF THE TFC AND WERE REPEATEDLY TOLD HE WAS 11 - 12 O'CLOCK AT 1500 FT EBOUND. WE WERE NOW ABOUT 3 MI FROM THE RWY END, STILL AT 2000 FT MSL (1600 FT AGL), AND WE EITHER HAD TO START A DSCNT OR ABANDON THE APCH. WE AGAIN ASKED APCH WHERE THE TFC WAS. HE SAID THE TFC WAS 1 MI 'DEAD 12 O'CLOCK.' WE CONTINUED TO SEARCH FOR THE TFC AND HOLD 2000 FT. BY NOW I WAS GETTING CONCERNED ABOUT NOT BEING ABLE TO GET DOWN IN TIME TO MAKE THE RWY. I WAS ALSO STARTING TO GET THE FEELING THAT A BAD SIT WAS DEVELOPING. WE ASKED ONCE MORE FOR THE TFC. I HAD DECIDED THAT IF WE DID NOT SEE THE TFC OR GET A CLR OF TFC ADVISORY, I WOULD ABANDON THE APCH. APCH REPLIED WE WERE 'RIGHT OVERHEAD' THE TFC AND HE WAS 'CLRING TO OUR R.' WE ACKNOWLEDGED THE XMISSION AND TOLD HIM WE WERE DSNDING OUT OF 2000 FT. HE ACKNOWLEDGED THAT AND THEN TOLD THE OTHER ACFT THAT THERE WAS SOME TFC (US) AND THAT HE SHOULD TURN TO THE SE (R). I THEN BUSIED MYSELF WITH THE TASK OF COMPLETING THE LNDG CHKLIST. AS I WAS GOING THROUGH 1500 FT MSL I LOOKED OUT OF MY L WINDOW AND THERE SAW THE TFC THAT WE WERE TOLD HAD CLRED TO OUR R. IT WAS A C150 TFC PATROL ACFT. HE WAS VERY SLIGHTLY ABOVE US AND VERY CLOSE LATERALLY. HE WAS ALSO IN A R TURN TOWARDS US. IT IS DIFFICULT TO ESTIMATE HORIZ DISTANCE BUT I WAS CLOSE ENOUGH THAT HAD I SAW A PERSON IN THE ACFT I WOULD HAVE CLRLY BEEN ABLE TO RECOGNIZE HIM (100-200 FT?). AFTER A SECOND OR TWO TO ASSIMILATE THE SIT, I PUSHED THE ACFT HARD OVER INTO A DSCNT TO AVOID WHAT ALMOST CERTAINLY WOULD HAVE BEEN A MIDAIR. AFTER I STRAIGHTENED OUT THE ACFT WE CALLED THE TFC, GOT SWITCHED TO TWR, CLRED AND LANDED. I VISITED THE CTL TWR AND WE LISTENED TO THE TAPE AND DISCUSSED THE INCIDENT. IT SEEMS THE SEPARATION STANDARDS FOR CLASS C AIRSPACE WERE NOT VIOLATED. THEY RPTEDLY ARE 500 FT VERT AND 'GREEN BTWN.' SINCE WE DID NOT COLLIDE, THERE WAS EVIDENTLY 'GREEN BTWN.' THE FACT THAT 2 VERY EXPERIENCED AND MOTIVATED PLTS CAN FAIL TO SPOT CALLED TFC IN VIRTUALLY UNLIMITED VISUAL CONDITIONS UNTIL THEY ALMOST COLLIDE, TO ME, POINTS UP THE WEAKNESSES IN THE SEPARATION STANDARDS FOR CLASS C AIRSPACE AND IN OVERDEPENDENCE ON 'SEE AND AVOID.'

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.