Narrative:

Departed ont on pom 1. Usual altitude restriction. At approximately 2 mi northwest of pom ATC advised 'VFR traffic 12 O'clock, 6 mi, no altitude.' neither first officer nor I could see anyone and I replied, 'looking, no contact. Please keep us advised.' shortly afterwards I caught a brief glimpse of a high wing single engine aircraft passing side window just below us at 9:30 and a 45 degree angle to our reverse course. I advised ATC and was given frequency change. Advised lax we would be filing a near midair collision report. It was subsequently filed. Factors: we were both looking 11-1 O'clock, but traffic probably was at 9-10 O'clock. Had we been looking at 9:30-10 O'clock, we might have seen him. But, sun was right at 12 O'clock and with the haze it was very difficult to see anything, so perhaps it would not have made a difference. We were very light and had a higher than normal pitch angle/climb rate (we were climbing at less than 4000 FPM). Although pitch attitude made seeing down difficult, it might have enabled us to miss other aircraft. Obviously, if other aircraft had altitude encoding, this probably would not have happened as the potential threat would have been recognized and a vector or climb restriction given or asked for. I do not know of anything else we could have done to prevent this, except perhaps request a vector around traffic. But, if you requested that for all VFR traffic (on the west coast), you would never get to destination.

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Original NASA ASRS Text

Title: CONFLICT BETWEEN ACR-MLG CLIMBING AND GA-SMA.

Narrative: DEPARTED ONT ON POM 1. USUAL ALT RESTRICTION. AT APPROX 2 MI NW OF POM ATC ADVISED 'VFR TFC 12 O'CLOCK, 6 MI, NO ALT.' NEITHER F/O NOR I COULD SEE ANYONE AND I REPLIED, 'LOOKING, NO CONTACT. PLEASE KEEP US ADVISED.' SHORTLY AFTERWARDS I CAUGHT A BRIEF GLIMPSE OF A HIGH WING SINGLE ENG ACFT PASSING SIDE WINDOW JUST BELOW US AT 9:30 AND A 45 DEG ANGLE TO OUR REVERSE COURSE. I ADVISED ATC AND WAS GIVEN FREQ CHANGE. ADVISED LAX WE WOULD BE FILING A NMAC RPT. IT WAS SUBSEQUENTLY FILED. FACTORS: WE WERE BOTH LOOKING 11-1 O'CLOCK, BUT TFC PROBABLY WAS AT 9-10 O'CLOCK. HAD WE BEEN LOOKING AT 9:30-10 O'CLOCK, WE MIGHT HAVE SEEN HIM. BUT, SUN WAS RIGHT AT 12 O'CLOCK AND WITH THE HAZE IT WAS VERY DIFFICULT TO SEE ANYTHING, SO PERHAPS IT WOULD NOT HAVE MADE A DIFFERENCE. WE WERE VERY LIGHT AND HAD A HIGHER THAN NORMAL PITCH ANGLE/CLB RATE (WE WERE CLBING AT LESS THAN 4000 FPM). ALTHOUGH PITCH ATTITUDE MADE SEEING DOWN DIFFICULT, IT MIGHT HAVE ENABLED US TO MISS OTHER ACFT. OBVIOUSLY, IF OTHER ACFT HAD ALT ENCODING, THIS PROBABLY WOULD NOT HAVE HAPPENED AS THE POTENTIAL THREAT WOULD HAVE BEEN RECOGNIZED AND A VECTOR OR CLB RESTRICTION GIVEN OR ASKED FOR. I DO NOT KNOW OF ANYTHING ELSE WE COULD HAVE DONE TO PREVENT THIS, EXCEPT PERHAPS REQUEST A VECTOR AROUND TFC. BUT, IF YOU REQUESTED THAT FOR ALL VFR TFC (ON THE W COAST), YOU WOULD NEVER GET TO DEST.

Data retrieved from NASA's ASRS site as of August 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.