Narrative:

VFR charter flight from salinas to sacramento executive and lincoln, ca. Receiving radar advisories from stockton approach at 8500 ft. My flight path would take us across the very busy arrs into the bay area. I normally cross this area at a lower altitude, but because of turbulence over the mountains, I continued at 8500 ft MSL. Upon initial contact with approach, I was told to inform him before I began a descent to sacramento. He also pointed out an air carrier B737 crossing from right to left. I acknowledged that I had visual contact with that traffic. I also saw the following aircraft. Approach informed me that the aircraft would be descending to 8000 ft and the crew reported they had my aircraft in sight. As I continued on my course and altitude the other aircraft (air carrier Y flight) appeared to be descending toward my aircraft on a collision course. I anticipated that he would descend below my flight path, but as he closed within 1 mi he still appeared to be above us in a descent. I decided it was time to exercise my emergency authority/authorized according to far 135.19 and began a climbing left turn out of his way. As I turned left to a course that was 90 degrees to aircraft Y's flight path, my right seat passenger said the other aircraft started a right climbing turn. ATC then asked if I had the other aircraft in sight. I replied that I was heading south (90 degrees away from his flight path) and no longer saw him. ATC asked if I was still going to sacramento. I replied that I was and turned back on the original course and altitude. By this time the next arrival traffic was pointed out approaching from the right. ATC asked if I would like to descend to 7500 ft. I replied that I would and that the other traffic was in sight. As I descended, ATC gave a phone number to both flight Y and to me. We are both to file an near midair collision report. Upon arrival at lincoln, I phoned stockton TRACON and reported to the supervisor. He asked if my aircraft was equipped with TCASII. I replied it was not. He told me that air carrier flight Y had leveled off at 9000 ft and was going to maintain 9000 ft until he passed me. I told him I never heard the crew or ATC state that and if I had realized he was maintaining 9000 ft, I would not have climbed. I still would have turned out of his way. I feel that if he planned to cross 500 ft over the top of my aircraft we would still be too close. Since, I assume, air carrier flight Y had TCASII they would have received a fly-up command when I started a climbing turn. From our visual perspective, both my right seat passenger and I perceived the aircraft Y in a descent until he pulled up and turned right. I do not know ATC's traffic situation at the time, but a lower altitude or a vector away from the other aircraft flight path might have prevented the need for evasive maneuvering. Supplemental information from acn 547314: on marvin 1 arrival to oak at 9000 ft, we were informed of traffic at 10 O'clock position, approximately 5 mi at 8500 ft. We reported 'traffic in sight' and were directed 'reference that traffic, cross catty intersection at 8000 ft.' we did not begin descent due to the position of the other aircraft. Shortly thereafter, the other aircraft began what appeared to be a climbing right turn. We began a climbing right turn to avoid collision, climbing to 10000 ft. TCASII did not give an RA, most likely due to our evasive maneuver. The other aircraft began a descending left turn and we returned to our cleared routing and altitude. We landed at oak without further incident.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT BTWN A C414A AND A XING B737-400 WITH BOTH FLC'S SUPPOSEDLY MAINTAINING VISUAL SEPARATION FROM EACH OTHER ON FREQ WITH APCH CTLR AT SCK, CA.

Narrative: VFR CHARTER FLT FROM SALINAS TO SACRAMENTO EXECUTIVE AND LINCOLN, CA. RECEIVING RADAR ADVISORIES FROM STOCKTON APCH AT 8500 FT. MY FLT PATH WOULD TAKE US ACROSS THE VERY BUSY ARRS INTO THE BAY AREA. I NORMALLY CROSS THIS AREA AT A LOWER ALT, BUT BECAUSE OF TURB OVER THE MOUNTAINS, I CONTINUED AT 8500 FT MSL. UPON INITIAL CONTACT WITH APCH, I WAS TOLD TO INFORM HIM BEFORE I BEGAN A DSCNT TO SACRAMENTO. HE ALSO POINTED OUT AN ACR B737 XING FROM R TO L. I ACKNOWLEDGED THAT I HAD VISUAL CONTACT WITH THAT TFC. I ALSO SAW THE FOLLOWING ACFT. APCH INFORMED ME THAT THE ACFT WOULD BE DSNDING TO 8000 FT AND THE CREW RPTED THEY HAD MY ACFT IN SIGHT. AS I CONTINUED ON MY COURSE AND ALT THE OTHER ACFT (ACR Y FLT) APPEARED TO BE DSNDING TOWARD MY ACFT ON A COLLISION COURSE. I ANTICIPATED THAT HE WOULD DSND BELOW MY FLT PATH, BUT AS HE CLOSED WITHIN 1 MI HE STILL APPEARED TO BE ABOVE US IN A DSCNT. I DECIDED IT WAS TIME TO EXERCISE MY EMER AUTH ACCORDING TO FAR 135.19 AND BEGAN A CLBING L TURN OUT OF HIS WAY. AS I TURNED L TO A COURSE THAT WAS 90 DEGS TO ACFT Y'S FLT PATH, MY R SEAT PAX SAID THE OTHER ACFT STARTED A R CLBING TURN. ATC THEN ASKED IF I HAD THE OTHER ACFT IN SIGHT. I REPLIED THAT I WAS HEADING S (90 DEGS AWAY FROM HIS FLT PATH) AND NO LONGER SAW HIM. ATC ASKED IF I WAS STILL GOING TO SACRAMENTO. I REPLIED THAT I WAS AND TURNED BACK ON THE ORIGINAL COURSE AND ALT. BY THIS TIME THE NEXT ARR TFC WAS POINTED OUT APCHING FROM THE R. ATC ASKED IF I WOULD LIKE TO DSND TO 7500 FT. I REPLIED THAT I WOULD AND THAT THE OTHER TFC WAS IN SIGHT. AS I DSNDED, ATC GAVE A PHONE NUMBER TO BOTH FLT Y AND TO ME. WE ARE BOTH TO FILE AN NMAC RPT. UPON ARR AT LINCOLN, I PHONED STOCKTON TRACON AND RPTED TO THE SUPVR. HE ASKED IF MY ACFT WAS EQUIPPED WITH TCASII. I REPLIED IT WAS NOT. HE TOLD ME THAT ACR FLT Y HAD LEVELED OFF AT 9000 FT AND WAS GOING TO MAINTAIN 9000 FT UNTIL HE PASSED ME. I TOLD HIM I NEVER HEARD THE CREW OR ATC STATE THAT AND IF I HAD REALIZED HE WAS MAINTAINING 9000 FT, I WOULD NOT HAVE CLBED. I STILL WOULD HAVE TURNED OUT OF HIS WAY. I FEEL THAT IF HE PLANNED TO CROSS 500 FT OVER THE TOP OF MY ACFT WE WOULD STILL BE TOO CLOSE. SINCE, I ASSUME, ACR FLT Y HAD TCASII THEY WOULD HAVE RECEIVED A FLY-UP COMMAND WHEN I STARTED A CLBING TURN. FROM OUR VISUAL PERSPECTIVE, BOTH MY R SEAT PAX AND I PERCEIVED THE ACFT Y IN A DSCNT UNTIL HE PULLED UP AND TURNED R. I DO NOT KNOW ATC'S TFC SIT AT THE TIME, BUT A LOWER ALT OR A VECTOR AWAY FROM THE OTHER ACFT FLT PATH MIGHT HAVE PREVENTED THE NEED FOR EVASIVE MANEUVERING. SUPPLEMENTAL INFO FROM ACN 547314: ON MARVIN 1 ARR TO OAK AT 9000 FT, WE WERE INFORMED OF TFC AT 10 O'CLOCK POS, APPROX 5 MI AT 8500 FT. WE RPTED 'TFC IN SIGHT' AND WERE DIRECTED 'REF THAT TFC, CROSS CATTY INTXN AT 8000 FT.' WE DID NOT BEGIN DSCNT DUE TO THE POS OF THE OTHER ACFT. SHORTLY THEREAFTER, THE OTHER ACFT BEGAN WHAT APPEARED TO BE A CLBING R TURN. WE BEGAN A CLBING R TURN TO AVOID COLLISION, CLBING TO 10000 FT. TCASII DID NOT GIVE AN RA, MOST LIKELY DUE TO OUR EVASIVE MANEUVER. THE OTHER ACFT BEGAN A DSNDING L TURN AND WE RETURNED TO OUR CLRED ROUTING AND ALT. WE LANDED AT OAK WITHOUT FURTHER INCIDENT.

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.