Air carrier has near midair collision with small aircraft in mixed WX conditions.

Attributes
ACN	152588
Time
Date	199007
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bli
State Reference	WA
Altitude	msl bound lower : 2200 msl bound upper : 2200
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute airway : yvr
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 210 flight time total : 7000 flight time type : 3000
ASRS Report	152588
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 100 vertical : 50
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

We were approaching our assigned altitude of 2000', heading north. Approach advised us of traffic at 11 O'clock, eastbound, altitude unknown. We were in a solid cloud layer at the time. Approach then said the target was 11:30, less than 1 mi. We broke out the overcast, but our forward vision was obstructed by a broken layer. We went through a small cloud and the target was directly ahead, at our altitude, approximately 300' away. I disconnected the autoplt and simultaneously turned left and pushed over, which caused us to pass behind and below the other aircraft (a single engine small aircraft). I don't believe the pilot never saw us (although [south]he probably heard us after was passed). We are convinced the pilot was not operating in legal VFR conditions. The controller told me later on the phone that they lost the target after our encounter.

Original NASA ASRS Text

Title: ACR HAS NMAC WITH SMA IN MIXED WX CONDITIONS.

Narrative: WE WERE APCHING OUR ASSIGNED ALT OF 2000', HDG N. APCH ADVISED US OF TFC AT 11 O'CLOCK, EBND, ALT UNKNOWN. WE WERE IN A SOLID CLOUD LAYER AT THE TIME. APCH THEN SAID THE TARGET WAS 11:30, LESS THAN 1 MI. WE BROKE OUT THE OVCST, BUT OUR FORWARD VISION WAS OBSTRUCTED BY A BROKEN LAYER. WE WENT THROUGH A SMALL CLOUD AND THE TARGET WAS DIRECTLY AHEAD, AT OUR ALT, APPROX 300' AWAY. I DISCONNECTED THE AUTOPLT AND SIMULTANEOUSLY TURNED LEFT AND PUSHED OVER, WHICH CAUSED US TO PASS BEHIND AND BELOW THE OTHER ACFT (A SINGLE ENG SMA). I DON'T BELIEVE THE PLT NEVER SAW US (ALTHOUGH [S]HE PROBABLY HEARD US AFTER WAS PASSED). WE ARE CONVINCED THE PLT WAS NOT OPERATING IN LEGAL VFR CONDITIONS. THE CTLR TOLD ME LATER ON THE PHONE THAT THEY LOST THE TARGET AFTER OUR ENCOUNTER.

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.