Narrative:

I departed cma at XI00 local on a VFR climb to 5000 ft eastbound towards vny VOR. Although the WX in cma was clear with good visibility, I had opted for an IFR flight plan because I knew I'd be flying with the sun in my eyes and it was likely to restrict my visibility. After reaching 5000 ft I was cleared direct vny VOR. Not long after that traffic was called at my 9 O'clock as (B737 or B757?). I reported it in sight and was instructed to maintain visual separation with it. Soon after, air carrier X reported me in sight and were given the same instruction to maintain visual separation. (I had been told that air carrier X would be descending.) I was indeed keeping the other aircraft in sight but I misjudged the convergence course that we were on. In an instant the situation seemed to change from normal to do something quick! In the second as I was deciding which way to turn to avoid them, a voice from air carrier X said that it looked like I was turning right into them. In fact I had not yet initiated a turn but an instant later I started a turn to pass behind the other aircraft. A voice from the air carrier X aircraft indicated I should have started my turn much earlier. Indeed I would have if I had not misjudged the closure rate. I had fully expected them to pass well east of me and at a lower altitude. However, the air carrier X crew had reported me in sight, were also instructed to maintain visual separation, and were on 'the left' in a converging situation. We obviously both misjudged to distance. If I had judged it better this wouldn't have happened. As to factors affecting this situation -- I was not overly tired, the aircraft was fully functioning. It was a human perception error.

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Original NASA ASRS Text

Title: PLT OF AN ATX BN2, ISLANDER, MISJUDGED THE ACR TFC AND MADE A QUICK TURN TO AVOID AN MLG ON DSCNT PASSING THROUGH RPTR'S FLT PATH. VISUAL SEPARATION IN USE.

Narrative: I DEPARTED CMA AT XI00 LCL ON A VFR CLB TO 5000 FT EBOUND TOWARDS VNY VOR. ALTHOUGH THE WX IN CMA WAS CLR WITH GOOD VISIBILITY, I HAD OPTED FOR AN IFR FLT PLAN BECAUSE I KNEW I'D BE FLYING WITH THE SUN IN MY EYES AND IT WAS LIKELY TO RESTRICT MY VISIBILITY. AFTER REACHING 5000 FT I WAS CLRED DIRECT VNY VOR. NOT LONG AFTER THAT TFC WAS CALLED AT MY 9 O'CLOCK AS (B737 OR B757?). I RPTED IT IN SIGHT AND WAS INSTRUCTED TO MAINTAIN VISUAL SEPARATION WITH IT. SOON AFTER, ACR X RPTED ME IN SIGHT AND WERE GIVEN THE SAME INSTRUCTION TO MAINTAIN VISUAL SEPARATION. (I HAD BEEN TOLD THAT ACR X WOULD BE DSNDING.) I WAS INDEED KEEPING THE OTHER ACFT IN SIGHT BUT I MISJUDGED THE CONVERGENCE COURSE THAT WE WERE ON. IN AN INSTANT THE SIT SEEMED TO CHANGE FROM NORMAL TO DO SOMETHING QUICK! IN THE SECOND AS I WAS DECIDING WHICH WAY TO TURN TO AVOID THEM, A VOICE FROM ACR X SAID THAT IT LOOKED LIKE I WAS TURNING RIGHT INTO THEM. IN FACT I HAD NOT YET INITIATED A TURN BUT AN INSTANT LATER I STARTED A TURN TO PASS BEHIND THE OTHER ACFT. A VOICE FROM THE ACR X ACFT INDICATED I SHOULD HAVE STARTED MY TURN MUCH EARLIER. INDEED I WOULD HAVE IF I HAD NOT MISJUDGED THE CLOSURE RATE. I HAD FULLY EXPECTED THEM TO PASS WELL E OF ME AND AT A LOWER ALT. HOWEVER, THE ACR X CREW HAD RPTED ME IN SIGHT, WERE ALSO INSTRUCTED TO MAINTAIN VISUAL SEPARATION, AND WERE ON 'THE L' IN A CONVERGING SIT. WE OBVIOUSLY BOTH MISJUDGED TO DISTANCE. IF I HAD JUDGED IT BETTER THIS WOULDN'T HAVE HAPPENED. AS TO FACTORS AFFECTING THIS SIT -- I WAS NOT OVERLY TIRED, THE ACFT WAS FULLY FUNCTIONING. IT WAS A HUMAN PERCEPTION ERROR.

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.