Narrative:

Time was XXXX local, day VMC. We were returning to lax from psp and were at 8000' MSL about 10 NM northwest of paradise VOR on the 256 degree right (V16). The first officer was flying and I was just finishing copying ATIS from lax. Suddenly the first officer made a comment and pushed forward on the wheel as a red and white aircraft crossed over the top of our cockpit coming headon from about 10:30-11 O'clock, my side. Obviously I had been occupied with writing the clearance. Vertical sep was about 200'. I called ont approach and reported that we had just had an aircraft miss us by 200'. A new voice came on frequency and said to stand by and they would get back to us. They never did. I informed them that I wanted to be sure they had the aircraft on radar by then since it was headed across a busy area between ont and norton AFB. It would appear that the controller on duty was reaching a saturation level, as she had been very busy, and immediately after my report, gave another aircraft an urgently worded traffic alert. This is my first real close one on an IFR flight plan. Clearly we were VMC and traffic avoidance was out responsibility, but I do find that it is very common to receive urgent traffic alerts from ATC when they have been distracted for some reason such as by a heavy workload. I find that many, many calls are for traffic which could not conceivably become a factor, and a significant few of the real hazards are missed completely. Last week I heard lax approach inform another aircraft that his response to a TCASII alert was unwarranted due to altitude sep available, and he responded that, to the contrary, the aircraft had been a threat. I also see quite a few occurrences where ATC considers 500-1000' vertical sep shown on mode C to be real sep. This is a very bad assumption, as many privately owned encoders are in use west/O legally required calibration.

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Original NASA ASRS Text

Title: CLOSE PROX COMMUTER-SMT GA-SMA 10 NORTHWEST OF PDZ ON V16.

Narrative: TIME WAS XXXX LCL, DAY VMC. WE WERE RETURNING TO LAX FROM PSP AND WERE AT 8000' MSL ABOUT 10 NM NW OF PARADISE VOR ON THE 256 DEG R (V16). THE F/O WAS FLYING AND I WAS JUST FINISHING COPYING ATIS FROM LAX. SUDDENLY THE F/O MADE A COMMENT AND PUSHED FORWARD ON THE WHEEL AS A RED AND WHITE ACFT CROSSED OVER THE TOP OF OUR COCKPIT COMING HEADON FROM ABOUT 10:30-11 O'CLOCK, MY SIDE. OBVIOUSLY I HAD BEEN OCCUPIED WITH WRITING THE CLRNC. VERT SEP WAS ABOUT 200'. I CALLED ONT APCH AND RPTED THAT WE HAD JUST HAD AN ACFT MISS US BY 200'. A NEW VOICE CAME ON FREQ AND SAID TO STAND BY AND THEY WOULD GET BACK TO US. THEY NEVER DID. I INFORMED THEM THAT I WANTED TO BE SURE THEY HAD THE ACFT ON RADAR BY THEN SINCE IT WAS HEADED ACROSS A BUSY AREA BTWN ONT AND NORTON AFB. IT WOULD APPEAR THAT THE CTLR ON DUTY WAS REACHING A SATURATION LEVEL, AS SHE HAD BEEN VERY BUSY, AND IMMEDIATELY AFTER MY RPT, GAVE ANOTHER ACFT AN URGENTLY WORDED TFC ALERT. THIS IS MY FIRST REAL CLOSE ONE ON AN IFR FLT PLAN. CLEARLY WE WERE VMC AND TFC AVOIDANCE WAS OUT RESPONSIBILITY, BUT I DO FIND THAT IT IS VERY COMMON TO RECEIVE URGENT TFC ALERTS FROM ATC WHEN THEY HAVE BEEN DISTRACTED FOR SOME REASON SUCH AS BY A HVY WORKLOAD. I FIND THAT MANY, MANY CALLS ARE FOR TFC WHICH COULD NOT CONCEIVABLY BECOME A FACTOR, AND A SIGNIFICANT FEW OF THE REAL HAZARDS ARE MISSED COMPLETELY. LAST WK I HEARD LAX APCH INFORM ANOTHER ACFT THAT HIS RESPONSE TO A TCASII ALERT WAS UNWARRANTED DUE TO ALT SEP AVAILABLE, AND HE RESPONDED THAT, TO THE CONTRARY, THE ACFT HAD BEEN A THREAT. I ALSO SEE QUITE A FEW OCCURRENCES WHERE ATC CONSIDERS 500-1000' VERT SEP SHOWN ON MODE C TO BE REAL SEP. THIS IS A VERY BAD ASSUMPTION, AS MANY PRIVATELY OWNED ENCODERS ARE IN USE W/O LEGALLY REQUIRED CALIBRATION.

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.