Narrative:

I was descending out of 4000 ft from the north for landing at sjc in my malibu mirage. I was in contact with bay approach and had just been passed off to sjc tower. I had been cleared to pass over the field at 2500 ft for a left downwind to runway 29. As I was making contact with sjc tower, I caught a glimpse of an airplane, perhaps a gray malibu, just underneath me as it passed below and behind my left wing. I estimate the altitude difference as between 100 and 200 ft with him either level or climbing and me descending. After landing, my passenger in the copilot seat mentioned seeing an airplane passing under the right hand side and also estimated a couple hundred ft separation. Had we been at the same altitude, we would have collided. Though both the passenger and I were scanning the sky, we did not observe the aircraft until too late for evasive action. I realize that ATC has no legal obligation to separate VFR traffic even though we were just above class C airspace and very near to a busy commercial airport. But I can tell you the experience is unsettling. I highly recommend that the FAA seriously consider taking on more responsibility for aircraft under VFR conditions in class B and C airspace and under flight following. When pilots request flight following, they are attempting to improve the safety of the entire airspace environment. ATC rarely denies requests for flight following but when they do, it is probably because of heavy traffic, just the time that we need separation services. I really believe that the extra manpwr required to provide true separation services would be minimal and well worth the cost in terms of safety. The extra workload to require separation services (as between IFR aircraft) should be small. But if controllers have no legal requirement to provide such separation, then it becomes less of a priority. Yet, many of our mid-airs have occurred in VFR conditions. If the pilots are asking for help in making the system safer by requesting flight following, let's get the government to play an appropriate role, one for which they are capable today.

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Original NASA ASRS Text

Title: SMA HAS NMAC WITH SMA WITHIN OR NEAR CLASS C AIRSPACE.

Narrative: I WAS DSNDING OUT OF 4000 FT FROM THE N FOR LNDG AT SJC IN MY MALIBU MIRAGE. I WAS IN CONTACT WITH BAY APCH AND HAD JUST BEEN PASSED OFF TO SJC TWR. I HAD BEEN CLRED TO PASS OVER THE FIELD AT 2500 FT FOR A L DOWNWIND TO RWY 29. AS I WAS MAKING CONTACT WITH SJC TWR, I CAUGHT A GLIMPSE OF AN AIRPLANE, PERHAPS A GRAY MALIBU, JUST UNDERNEATH ME AS IT PASSED BELOW AND BEHIND MY L WING. I ESTIMATE THE ALT DIFFERENCE AS BTWN 100 AND 200 FT WITH HIM EITHER LEVEL OR CLBING AND ME DSNDING. AFTER LNDG, MY PAX IN THE COPLT SEAT MENTIONED SEEING AN AIRPLANE PASSING UNDER THE R HAND SIDE AND ALSO ESTIMATED A COUPLE HUNDRED FT SEPARATION. HAD WE BEEN AT THE SAME ALT, WE WOULD HAVE COLLIDED. THOUGH BOTH THE PAX AND I WERE SCANNING THE SKY, WE DID NOT OBSERVE THE ACFT UNTIL TOO LATE FOR EVASIVE ACTION. I REALIZE THAT ATC HAS NO LEGAL OBLIGATION TO SEPARATE VFR TFC EVEN THOUGH WE WERE JUST ABOVE CLASS C AIRSPACE AND VERY NEAR TO A BUSY COMMERCIAL ARPT. BUT I CAN TELL YOU THE EXPERIENCE IS UNSETTLING. I HIGHLY RECOMMEND THAT THE FAA SERIOUSLY CONSIDER TAKING ON MORE RESPONSIBILITY FOR ACFT UNDER VFR CONDITIONS IN CLASS B AND C AIRSPACE AND UNDER FLT FOLLOWING. WHEN PLTS REQUEST FLT FOLLOWING, THEY ARE ATTEMPTING TO IMPROVE THE SAFETY OF THE ENTIRE AIRSPACE ENVIRONMENT. ATC RARELY DENIES REQUESTS FOR FLT FOLLOWING BUT WHEN THEY DO, IT IS PROBABLY BECAUSE OF HEAVY TFC, JUST THE TIME THAT WE NEED SEPARATION SVCS. I REALLY BELIEVE THAT THE EXTRA MANPWR REQUIRED TO PROVIDE TRUE SEPARATION SVCS WOULD BE MINIMAL AND WELL WORTH THE COST IN TERMS OF SAFETY. THE EXTRA WORKLOAD TO REQUIRE SEPARATION SVCS (AS BTWN IFR ACFT) SHOULD BE SMALL. BUT IF CTLRS HAVE NO LEGAL REQUIREMENT TO PROVIDE SUCH SEPARATION, THEN IT BECOMES LESS OF A PRIORITY. YET, MANY OF OUR MID-AIRS HAVE OCCURRED IN VFR CONDITIONS. IF THE PLTS ARE ASKING FOR HELP IN MAKING THE SYS SAFER BY REQUESTING FLT FOLLOWING, LET'S GET THE GOV TO PLAY AN APPROPRIATE ROLE, ONE FOR WHICH THEY ARE CAPABLE TODAY.

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.