Narrative:

I was level at 4500 ft, heading 270 degrees. ATC advised me of traffic 2 O'clock position, climbing to 4000 ft (airbus). I had traffic in sight. He was flying sebound. We were rapidly converging. It looked like if we both maintain courses we were either going to collide or I was going to pass over him, but too close. I decided to descend and turn slightly to the right. My decision to descend was based on the fact that the other aircraft still appeared to be climbing and on the performance of my aircraft (I could control my rate of descent much better than my rate of climb (maximum 750 FPM). I contacted approach and requested a descent to avoid wake turbulence. He was busy with other traffic and there was no response. I requested it again, and after not getting a response the second time, I turned about 10-20 degrees to the right and began to descend at approximately 1500-2000 FPM. My intention was to turn back to an easterly heading, but at that time ATC contacted me and instructed me to fly heading 320 degrees and maintain current altitude (my altitude at that moment was 3900 ft). I was later given a phone number to call, and ATC filed a pilot deviation report. I feel that had I not deviated, things would have been much worse, but I also think that I should have done it a little sooner. In my judgement, maintaining a 270 degree course at 4500 ft was going to make me fly (cross) exactly over the airbus and the planned 500 ft separation (which in reality could be less due to altimeter errors) would have constituted an near midair collision.

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Original NASA ASRS Text

Title: PIPER PA28 PLT, WHILE IN CLASS B AIRSPACE, DEVIATED FROM ASSIGNED HDG AND ALT AFTER OBSERVING AN AIRBUS RPTED TO BE CLBING TO AN ALT 500 FT BELOW. THIS ACTION CAUSED LOSS OF SEPARATION SINCE RPTR DSNDED INTO AND THROUGH THE AIRBUS ALT.

Narrative: I WAS LEVEL AT 4500 FT, HDG 270 DEGS. ATC ADVISED ME OF TFC 2 O'CLOCK POS, CLBING TO 4000 FT (AIRBUS). I HAD TFC IN SIGHT. HE WAS FLYING SEBOUND. WE WERE RAPIDLY CONVERGING. IT LOOKED LIKE IF WE BOTH MAINTAIN COURSES WE WERE EITHER GOING TO COLLIDE OR I WAS GOING TO PASS OVER HIM, BUT TOO CLOSE. I DECIDED TO DSND AND TURN SLIGHTLY TO THE R. MY DECISION TO DSND WAS BASED ON THE FACT THAT THE OTHER ACFT STILL APPEARED TO BE CLBING AND ON THE PERFORMANCE OF MY ACFT (I COULD CTL MY RATE OF DSCNT MUCH BETTER THAN MY RATE OF CLB (MAX 750 FPM). I CONTACTED APCH AND REQUESTED A DSCNT TO AVOID WAKE TURB. HE WAS BUSY WITH OTHER TFC AND THERE WAS NO RESPONSE. I REQUESTED IT AGAIN, AND AFTER NOT GETTING A RESPONSE THE SECOND TIME, I TURNED ABOUT 10-20 DEGS TO THE R AND BEGAN TO DSND AT APPROX 1500-2000 FPM. MY INTENTION WAS TO TURN BACK TO AN EASTERLY HDG, BUT AT THAT TIME ATC CONTACTED ME AND INSTRUCTED ME TO FLY HDG 320 DEGS AND MAINTAIN CURRENT ALT (MY ALT AT THAT MOMENT WAS 3900 FT). I WAS LATER GIVEN A PHONE NUMBER TO CALL, AND ATC FILED A PLTDEV RPT. I FEEL THAT HAD I NOT DEVIATED, THINGS WOULD HAVE BEEN MUCH WORSE, BUT I ALSO THINK THAT I SHOULD HAVE DONE IT A LITTLE SOONER. IN MY JUDGEMENT, MAINTAINING A 270 DEG COURSE AT 4500 FT WAS GOING TO MAKE ME FLY (CROSS) EXACTLY OVER THE AIRBUS AND THE PLANNED 500 FT SEPARATION (WHICH IN REALITY COULD BE LESS DUE TO ALTIMETER ERRORS) WOULD HAVE CONSTITUTED AN NMAC.

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.