2 smas had an near midair collision in VMC. The reporting aircraft was in contact with bay TRACON.

Attributes
ACN	220801
Time
Date	199209
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : sjc airport : pao
State Reference	CA
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	VFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 25 flight time total : 119 flight time type : 12
ASRS Report	220801
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 50 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

While abeam san jose airport, I advised bay I was descending from 4500 to 3000. As I came abeam of mission peak, bay informed me that I had traffic at 12 O'clock, same altitude, 1 1/2 mi opposite direction. I had been scanning for traffic and had already spotted several other aircraft in my vicinity, but could not locate the traffic at 12 O'clock. Bay announced the traffic was half a mi and closing, and advised immediate descent. I immediately complied with bay's advisory. I had descended 200 ft when I saw another plane flash past roughly 100-200 ft below me and slightly to my left. As it passed behind me, bay advised that the traffic appeared to have passed my position. Bay requested confirmation that the aircraft was below me, and I confirmed this. Bay then advised other aircraft that the plane that had just passed me was at a lower altitude than its transponder was indicating. I had previously confirmed on the flight down and again on my flight back that my own transponder was indicating the correct altitude.

Original NASA ASRS Text

Title: 2 SMAS HAD AN NMAC IN VMC. THE RPTING ACFT WAS IN CONTACT WITH BAY TRACON.

Narrative: WHILE ABEAM SAN JOSE ARPT, I ADVISED BAY I WAS DSNDING FROM 4500 TO 3000. AS I CAME ABEAM OF MISSION PEAK, BAY INFORMED ME THAT I HAD TFC AT 12 O'CLOCK, SAME ALT, 1 1/2 MI OPPOSITE DIRECTION. I HAD BEEN SCANNING FOR TFC AND HAD ALREADY SPOTTED SEVERAL OTHER ACFT IN MY VICINITY, BUT COULD NOT LOCATE THE TFC AT 12 O'CLOCK. BAY ANNOUNCED THE TFC WAS HALF A MI AND CLOSING, AND ADVISED IMMEDIATE DSCNT. I IMMEDIATELY COMPLIED WITH BAY'S ADVISORY. I HAD DSNDED 200 FT WHEN I SAW ANOTHER PLANE FLASH PAST ROUGHLY 100-200 FT BELOW ME AND SLIGHTLY TO MY L. AS IT PASSED BEHIND ME, BAY ADVISED THAT THE TFC APPEARED TO HAVE PASSED MY POS. BAY REQUESTED CONFIRMATION THAT THE ACFT WAS BELOW ME, AND I CONFIRMED THIS. BAY THEN ADVISED OTHER ACFT THAT THE PLANE THAT HAD JUST PASSED ME WAS AT A LOWER ALT THAN ITS TRANSPONDER WAS INDICATING. I HAD PREVIOUSLY CONFIRMED ON THE FLT DOWN AND AGAIN ON MY FLT BACK THAT MY OWN TRANSPONDER WAS INDICATING THE CORRECT ALT.

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.