Pilot of small aircraft has near midair collision with small transport while at cruise flight.

Attributes
ACN	409142
Time
Date	199807
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : vny
State Reference	CA
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 50 flight time total : 4400 flight time type : 25
ASRS Report	409142
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Miss Distance	horizontal : 300 vertical : 300

Narrative:

Fly VFR at 3200 ft MSL (approximately 1700 ft AGL) wbound over pasadena in 30+ mi visibility, no ceiling. I cleared to make a left turn (looking aft to about 8 O'clock position). After establishing a 30 degree bank turn, I looked back forward and saw a light twin (C310, or baron) pass below and to my right. He must have been below and behind me when I initiated the turn. Non evasive action was taken or required, but I wish I had known he was back there before I made the turn. Most of my experience is in faster moving aircraft, and I wasn't in the habit of clearing behind me before making turns. I was monitoring socal on 125.5 but not in contact. I was never called out as traffic to any other aircraft and was squawking 3/C with code 1200. I suspect the twin was VFR on account of his altitude. The twin was probably at 3000 ft, wbound, and I have no indication he ever saw me. I had strobe lights on, but it was XA00 on a bright summer day.

Original NASA ASRS Text

Title: PLT OF SMA HAS NMAC WITH SMT WHILE AT CRUISE FLT.

Narrative: FLY VFR AT 3200 FT MSL (APPROX 1700 FT AGL) WBOUND OVER PASADENA IN 30+ MI VISIBILITY, NO CEILING. I CLRED TO MAKE A L TURN (LOOKING AFT TO ABOUT 8 O'CLOCK POS). AFTER ESTABLISHING A 30 DEG BANK TURN, I LOOKED BACK FORWARD AND SAW A LIGHT TWIN (C310, OR BARON) PASS BELOW AND TO MY R. HE MUST HAVE BEEN BELOW AND BEHIND ME WHEN I INITIATED THE TURN. NON EVASIVE ACTION WAS TAKEN OR REQUIRED, BUT I WISH I HAD KNOWN HE WAS BACK THERE BEFORE I MADE THE TURN. MOST OF MY EXPERIENCE IS IN FASTER MOVING ACFT, AND I WASN'T IN THE HABIT OF CLRING BEHIND ME BEFORE MAKING TURNS. I WAS MONITORING SOCAL ON 125.5 BUT NOT IN CONTACT. I WAS NEVER CALLED OUT AS TFC TO ANY OTHER ACFT AND WAS SQUAWKING 3/C WITH CODE 1200. I SUSPECT THE TWIN WAS VFR ON ACCOUNT OF HIS ALT. THE TWIN WAS PROBABLY AT 3000 FT, WBOUND, AND I HAVE NO INDICATION HE EVER SAW ME. I HAD STROBE LIGHTS ON, BUT IT WAS XA00 ON A BRIGHT SUMMER DAY.

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.