Narrative:

I was being radar vectored by socal approach to lax VOR while on an IFR tower en route flight plan from sna to vny airport flying at 4000 ft. There was a broken layer of clouds at our altitude and we were punching in and out of them. Shortly after entering a zone of clear sky, the socal controller advised us of traffic at 12 O'clock. I looked up from the foggles that I was wearing to see a yellow low wing light aircraft about 300 yards ahead of me and holding the same heading as I was. The beech V35B that I was flying was indicating 165 KTS. The traffic must have been climbing, and therefore flying at a considerably slower speed than I, because my rate of closure on it was extremely fast. It took me 1-2 seconds to realize that, if I didn't immediately alter my course, I would have chewed into the other aircraft's tail. I immediately pulled up and turned to the left to avoid the airplane. As I passed above and to the left of it, I keyed the microphone and said to socal, 'boy, that was really close!' the controller apologized and said that he had not seen the other aircraft. I understood this to mean that he had not seen the other aircraft until just before advising us of it. My safety pilot never saw the other aircraft either. The flight continued to vny without further incident. The problem (ie, the near miss) was caused primarily by the failure of the socal controller to see the traffic soon enough to provide me with adequate warning of its presence. My safety pilot was prevented from seeing the traffic because her forward view of it was blocked by our own aircraft's structure as the traffic ascended to a position in front of us. Adding to the problem of seeing the emerging traffic conflict was the broken cloud layer through which we had just flown, the WX conditions provided for a dangerous mix of VFR and IFR traffic in close proximity. In WX conditions such as that in which we were flying, which really constituted a juxtapositioning of IMC and VMC conditions, vigilance by the flight crew is clearly not always sufficient to provide for traffic separation that was not supplied by socal at that time. In the future, socal could prevent this type of event from occurring by maintaining a higher than usual level of vigilance to separate IFR and VFR aircraft when the cloud conditions in the area are likely to present barriers to visual see and avoid procedures.

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Original NASA ASRS Text

Title: NMAC BTWN A BEECH V35B LEVEL AT 4000 FT MSL, UNDER IFR IN AND OUT OF CLOUDS IN CLASS B AIRSPACE, AND A SINGLE ENG LOW WING ACFT AHEAD CLBING IN THE SAME DIRECTION. RPTR TOOK EVASIVE ACTION TO AVOID THE OTHER ACFT.

Narrative: I WAS BEING RADAR VECTORED BY SOCAL APCH TO LAX VOR WHILE ON AN IFR TWR ENRTE FLT PLAN FROM SNA TO VNY ARPT FLYING AT 4000 FT. THERE WAS A BROKEN LAYER OF CLOUDS AT OUR ALT AND WE WERE PUNCHING IN AND OUT OF THEM. SHORTLY AFTER ENTERING A ZONE OF CLR SKY, THE SOCAL CTLR ADVISED US OF TFC AT 12 O'CLOCK. I LOOKED UP FROM THE FOGGLES THAT I WAS WEARING TO SEE A YELLOW LOW WING LIGHT ACFT ABOUT 300 YARDS AHEAD OF ME AND HOLDING THE SAME HDG AS I WAS. THE BEECH V35B THAT I WAS FLYING WAS INDICATING 165 KTS. THE TFC MUST HAVE BEEN CLBING, AND THEREFORE FLYING AT A CONSIDERABLY SLOWER SPD THAN I, BECAUSE MY RATE OF CLOSURE ON IT WAS EXTREMELY FAST. IT TOOK ME 1-2 SECONDS TO REALIZE THAT, IF I DIDN'T IMMEDIATELY ALTER MY COURSE, I WOULD HAVE CHEWED INTO THE OTHER ACFT'S TAIL. I IMMEDIATELY PULLED UP AND TURNED TO THE L TO AVOID THE AIRPLANE. AS I PASSED ABOVE AND TO THE L OF IT, I KEYED THE MIKE AND SAID TO SOCAL, 'BOY, THAT WAS REALLY CLOSE!' THE CTLR APOLOGIZED AND SAID THAT HE HAD NOT SEEN THE OTHER ACFT. I UNDERSTOOD THIS TO MEAN THAT HE HAD NOT SEEN THE OTHER ACFT UNTIL JUST BEFORE ADVISING US OF IT. MY SAFETY PLT NEVER SAW THE OTHER ACFT EITHER. THE FLT CONTINUED TO VNY WITHOUT FURTHER INCIDENT. THE PROB (IE, THE NEAR MISS) WAS CAUSED PRIMARILY BY THE FAILURE OF THE SOCAL CTLR TO SEE THE TFC SOON ENOUGH TO PROVIDE ME WITH ADEQUATE WARNING OF ITS PRESENCE. MY SAFETY PLT WAS PREVENTED FROM SEEING THE TFC BECAUSE HER FORWARD VIEW OF IT WAS BLOCKED BY OUR OWN ACFT'S STRUCTURE AS THE TFC ASCENDED TO A POS IN FRONT OF US. ADDING TO THE PROB OF SEEING THE EMERGING TFC CONFLICT WAS THE BROKEN CLOUD LAYER THROUGH WHICH WE HAD JUST FLOWN, THE WX CONDITIONS PROVIDED FOR A DANGEROUS MIX OF VFR AND IFR TFC IN CLOSE PROX. IN WX CONDITIONS SUCH AS THAT IN WHICH WE WERE FLYING, WHICH REALLY CONSTITUTED A JUXTAPOSITIONING OF IMC AND VMC CONDITIONS, VIGILANCE BY THE FLC IS CLRLY NOT ALWAYS SUFFICIENT TO PROVIDE FOR TFC SEPARATION THAT WAS NOT SUPPLIED BY SOCAL AT THAT TIME. IN THE FUTURE, SOCAL COULD PREVENT THIS TYPE OF EVENT FROM OCCURRING BY MAINTAINING A HIGHER THAN USUAL LEVEL OF VIGILANCE TO SEPARATE IFR AND VFR ACFT WHEN THE CLOUD CONDITIONS IN THE AREA ARE LIKELY TO PRESENT BARRIERS TO VISUAL SEE AND AVOID PROCS.

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.