Narrative:

While on a vector by coast approach to sna from lax 5000 ft MSL heading 110 degree in cruise flight, both flight crew members idented an approaching aircraft at 11 O'clock position 1/4 mi on converging course at same altitude (5000) and climbing slowly. We took evasive action, right turn 30 degree and descent of 500 ft to avoid collision. Inquired approach of radar contact with said other aircraft. A response of 'nothing on screen' was told. Advised ATC of situation and continued with the rest of flight.

Google
 

Original NASA ASRS Text

Title: FLC OF COMMUTER DSNDED 500 FT AND MADE TURN TO AVOID TFC. NO RADAR CONTACT WITH TFC BY TRACON.

Narrative: WHILE ON A VECTOR BY COAST APCH TO SNA FROM LAX 5000 FT MSL HDG 110 DEG IN CRUISE FLT, BOTH FLC MEMBERS IDENTED AN APCHING ACFT AT 11 O'CLOCK POS 1/4 MI ON CONVERGING COURSE AT SAME ALT (5000) AND CLBING SLOWLY. WE TOOK EVASIVE ACTION, R TURN 30 DEG AND DSNT OF 500 FT TO AVOID COLLISION. INQUIRED APCH OF RADAR CONTACT WITH SAID OTHER ACFT. A RESPONSE OF 'NOTHING ON SCREEN' WAS TOLD. ADVISED ATC OF SITUATION AND CONTINUED WITH THE REST OF FLT.

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.