Narrative:

We were en route to burbank from bullhead city. The socal frequency was 134.2. The TCASII had a strange looking target approaching our position, outside the ring yet, but coming straight for us. We were just north of the ridge. (2 aircraft were on TCASII, but appeared to be 1.) socal called our traffic at 5000 ft. Our clearance was to 6000 ft and a heading of 160 degrees. We were there. The TCASII did not like this, as the target crossed the ring into our space. The TCASII said our target was at our altitude, though socal called it 1000 ft below us. It was clear and I got a visual on the cessna at 5000 ft. We could not see the one that was at our altitude and coming straight at us. I began to descend and turn away, first left then right, trying to get away from the target at our altitude, prompted by TCASII also. I don't believe socal saw the VFR traffic at our altitude, though he did call the IFR traffic below us. I don't believe we broke any rules, but the situation scared me and going into burbank and ontario we usually get a TCASII solution at least once every trip, unless it is IFR conditions. The target socal called was there and an additional target was directly above him, which I believe ATC could not see. He vectored us toward that target and told us not to leave 6000 ft. The TCASII saved this day.

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Original NASA ASRS Text

Title: B737 FLC INITIATE EVASIVE MANEUVERS AWAY FROM UNIDENTED TCASII ACFT AT SAME ALT, DISREGARDING SCT CLRNC TO MAINTAIN ASSIGNED ALT.

Narrative: WE WERE ENRTE TO BURBANK FROM BULLHEAD CITY. THE SOCAL FREQ WAS 134.2. THE TCASII HAD A STRANGE LOOKING TARGET APCHING OUR POS, OUTSIDE THE RING YET, BUT COMING STRAIGHT FOR US. WE WERE JUST N OF THE RIDGE. (2 ACFT WERE ON TCASII, BUT APPEARED TO BE 1.) SOCAL CALLED OUR TFC AT 5000 FT. OUR CLRNC WAS TO 6000 FT AND A HDG OF 160 DEGS. WE WERE THERE. THE TCASII DID NOT LIKE THIS, AS THE TARGET CROSSED THE RING INTO OUR SPACE. THE TCASII SAID OUR TARGET WAS AT OUR ALT, THOUGH SOCAL CALLED IT 1000 FT BELOW US. IT WAS CLR AND I GOT A VISUAL ON THE CESSNA AT 5000 FT. WE COULD NOT SEE THE ONE THAT WAS AT OUR ALT AND COMING STRAIGHT AT US. I BEGAN TO DSND AND TURN AWAY, FIRST L THEN R, TRYING TO GET AWAY FROM THE TARGET AT OUR ALT, PROMPTED BY TCASII ALSO. I DON'T BELIEVE SOCAL SAW THE VFR TFC AT OUR ALT, THOUGH HE DID CALL THE IFR TFC BELOW US. I DON'T BELIEVE WE BROKE ANY RULES, BUT THE SIT SCARED ME AND GOING INTO BURBANK AND ONTARIO WE USUALLY GET A TCASII SOLUTION AT LEAST ONCE EVERY TRIP, UNLESS IT IS IFR CONDITIONS. THE TARGET SOCAL CALLED WAS THERE AND AN ADDITIONAL TARGET WAS DIRECTLY ABOVE HIM, WHICH I BELIEVE ATC COULD NOT SEE. HE VECTORED US TOWARD THAT TARGET AND TOLD US NOT TO LEAVE 6000 FT. THE TCASII SAVED THIS DAY.

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.