Narrative:

After departing pao runway 30 with a right turn out at the dumbarton bridge, I proceeded on a course nne toward lvk airport. I stayed under 2000 ft until I crossed the water (bay) then climbed to get above a layer of mist. At 12:30 O'clock position moving to my 11 O'clock position, I encountered a commercial airliner at approximately my altitude and 1 mi away -- closing fast. The airliner banked approximately 70 degrees to the right and I did the same -- an aggressive climb and turn to my right. Shortly thereafter, pao tower released me to contact center for flight following. There was no mention of the traffic by pao's tower to me. I immediately requested flight following (VFR) from bay approach. Their controller subsequently informed me that they observed abrupt changes in my altitude (mode C) but made no mention of the potential conflict with an airliner. When I arrived in sacramento at sac airport, I took the airplane in to have the transponder's mode C checked. No problem with mode C. Contributing factors: 1) mist below approximately 300 ft MSL. 2) center assumed (my opinion) that my mode C was erratic when, in fact, I climbed rapidly to get above the poor visibility.

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Original NASA ASRS Text

Title: AN EXPERIMENTAL ACFT PVT PLT HAS AN NMAC WITH A B737 WHILE XING THE APCH RTE TO OAK ARPT AT OR NEAR 4000 FT. ESE OF OAK, CA.

Narrative: AFTER DEPARTING PAO RWY 30 WITH A R TURN OUT AT THE DUMBARTON BRIDGE, I PROCEEDED ON A COURSE NNE TOWARD LVK ARPT. I STAYED UNDER 2000 FT UNTIL I CROSSED THE WATER (BAY) THEN CLBED TO GET ABOVE A LAYER OF MIST. AT 12:30 O'CLOCK POS MOVING TO MY 11 O'CLOCK POS, I ENCOUNTERED A COMMERCIAL AIRLINER AT APPROX MY ALT AND 1 MI AWAY -- CLOSING FAST. THE AIRLINER BANKED APPROX 70 DEGS TO THE R AND I DID THE SAME -- AN AGGRESSIVE CLB AND TURN TO MY R. SHORTLY THEREAFTER, PAO TWR RELEASED ME TO CONTACT CTR FOR FLT FOLLOWING. THERE WAS NO MENTION OF THE TFC BY PAO'S TWR TO ME. I IMMEDIATELY REQUESTED FLT FOLLOWING (VFR) FROM BAY APCH. THEIR CTLR SUBSEQUENTLY INFORMED ME THAT THEY OBSERVED ABRUPT CHANGES IN MY ALT (MODE C) BUT MADE NO MENTION OF THE POTENTIAL CONFLICT WITH AN AIRLINER. WHEN I ARRIVED IN SACRAMENTO AT SAC ARPT, I TOOK THE AIRPLANE IN TO HAVE THE XPONDER'S MODE C CHKED. NO PROB WITH MODE C. CONTRIBUTING FACTORS: 1) MIST BELOW APPROX 300 FT MSL. 2) CTR ASSUMED (MY OPINION) THAT MY MODE C WAS ERRATIC WHEN, IN FACT, I CLBED RAPIDLY TO GET ABOVE THE POOR VISIBILITY.

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.