Narrative:

I was flying VFR from sql to sjc. I was handed off to moffett tower by pao tower -- requested VFR transition through nuq air traffic area en route sjc. Nuq asked that I maintain VFR at or below 1500 ft. Directly over moffett, I suddenly saw another aircraft just below the end of my right wing, coming directly at me very fast. It came into my view and passed a few ft from the end of my right wing in less than a second. I thought when I first saw it, that it would hit me. It came so close that I did not see the entire aircraft. It was a grey turboprop with wingtip tanks. It was in a hard left turn -- I can't say if it was trying to miss me or just in a climbing turn. I reported the miss immediately to nuq tower. They replied instantly that their 'radar' had shown a separation of more than 300 ft. They said the aircraft was doing a go around. Since I did not believe their instant evaluation of the miss distance, I did not press the point and continued on to sjc where I landed. I suspect that the other aircraft was on UHF or was doing a ground controled approach and missed approach, or had done an extreme pull-up -- possibly to the surprise of the tower personnel -- and had narrowly missed me before the tower had a chance to warn me. I had not been advised by nuq tower of other traffic and had seen none although I remember that there was one other transmission on the frequency that was unintelligible to me.

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Original NASA ASRS Text

Title: AN SMA HAD AN NMAC WITH AN UNKNOWN ACFT DIRECTLY OVER A MIL ARPT.

Narrative: I WAS FLYING VFR FROM SQL TO SJC. I WAS HANDED OFF TO MOFFETT TWR BY PAO TWR -- REQUESTED VFR TRANSITION THROUGH NUQ ATA ENRTE SJC. NUQ ASKED THAT I MAINTAIN VFR AT OR BELOW 1500 FT. DIRECTLY OVER MOFFETT, I SUDDENLY SAW ANOTHER ACFT JUST BELOW THE END OF MY R WING, COMING DIRECTLY AT ME VERY FAST. IT CAME INTO MY VIEW AND PASSED A FEW FT FROM THE END OF MY R WING IN LESS THAN A SECOND. I THOUGHT WHEN I FIRST SAW IT, THAT IT WOULD HIT ME. IT CAME SO CLOSE THAT I DID NOT SEE THE ENTIRE ACFT. IT WAS A GREY TURBOPROP WITH WINGTIP TANKS. IT WAS IN A HARD L TURN -- I CAN'T SAY IF IT WAS TRYING TO MISS ME OR JUST IN A CLBING TURN. I RPTED THE MISS IMMEDIATELY TO NUQ TWR. THEY REPLIED INSTANTLY THAT THEIR 'RADAR' HAD SHOWN A SEPARATION OF MORE THAN 300 FT. THEY SAID THE ACFT WAS DOING A GAR. SINCE I DID NOT BELIEVE THEIR INSTANT EVALUATION OF THE MISS DISTANCE, I DID NOT PRESS THE POINT AND CONTINUED ON TO SJC WHERE I LANDED. I SUSPECT THAT THE OTHER ACFT WAS ON UHF OR WAS DOING A GND CTLED APCH AND MISSED APCH, OR HAD DONE AN EXTREME PULL-UP -- POSSIBLY TO THE SURPRISE OF THE TWR PERSONNEL -- AND HAD NARROWLY MISSED ME BEFORE THE TWR HAD A CHANCE TO WARN ME. I HAD NOT BEEN ADVISED BY NUQ TWR OF OTHER TFC AND HAD SEEN NONE ALTHOUGH I REMEMBER THAT THERE WAS ONE OTHER XMISSION ON THE FREQ THAT WAS UNINTELLIGIBLE TO ME.

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.