2 uncontrolled smas had an near midair collision in a highly traveled VFR corridor.

Attributes
ACN	248690
Time
Date	199308
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : oak airport : hwd
State Reference	CA
Altitude	msl bound lower : 3200 msl bound upper : 3200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak tower : hya
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 40 flight time total : 390 flight time type : 100
ASRS Report	248690
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was descending along V107 bound for hwd. I had monitored bay approach from several mi out, but as I was well outside all arsa/TCA and air traffic area's, chose not to contact them. Proceeding north, I continued my descent to remain at VFR cloud clearance. Passing rhv I noticed no obvious activity. Near mison, I looked down at a chart briefly (2-3 seconds). Upon looking up to resume my scan, I saw an small aircraft approximately 100-150 yards at my 9 O'clock position moving to 10 O'clock position, converging at my altitude. I immediately executed a climbing right turn (estimated 50-60 degree bank) and increased power. Upon completing my turn, scanning for the small aircraft, found him on his original flight path. My errors may have been: 1) not contacting approach. 2) head inside when in a busy corridor, and 3) insufficient scan.

Original NASA ASRS Text

Title: 2 UNCTLED SMAS HAD AN NMAC IN A HIGHLY TRAVELED VFR CORRIDOR.

Narrative: I WAS DSNDING ALONG V107 BOUND FOR HWD. I HAD MONITORED BAY APCH FROM SEVERAL MI OUT, BUT AS I WAS WELL OUTSIDE ALL ARSA/TCA AND ATA'S, CHOSE NOT TO CONTACT THEM. PROCEEDING N, I CONTINUED MY DSCNT TO REMAIN AT VFR CLOUD CLRNC. PASSING RHV I NOTICED NO OBVIOUS ACTIVITY. NEAR MISON, I LOOKED DOWN AT A CHART BRIEFLY (2-3 SECONDS). UPON LOOKING UP TO RESUME MY SCAN, I SAW AN SMA APPROX 100-150 YARDS AT MY 9 O'CLOCK POS MOVING TO 10 O'CLOCK POS, CONVERGING AT MY ALT. I IMMEDIATELY EXECUTED A CLBING R TURN (ESTIMATED 50-60 DEG BANK) AND INCREASED PWR. UPON COMPLETING MY TURN, SCANNING FOR THE SMA, FOUND HIM ON HIS ORIGINAL FLT PATH. MY ERRORS MAY HAVE BEEN: 1) NOT CONTACTING APCH. 2) HEAD INSIDE WHEN IN A BUSY CORRIDOR, AND 3) INSUFFICIENT SCAN.

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.