Aircraft Y VFR in IMC had less than standard separation with air carrier X. Pilot deviation.

Attributes
ACN	245809
Time
Date	199307
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : pdx
State Reference	OR
Altitude	msl bound lower : 7000 msl bound upper : 7000
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : pdx
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft
Flight Phase	descent other
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 8
ASRS Report	245809
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe inflight encounter : vfr in imc non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was working the south airspace at portland, or, TRACON. Air carrier checked in 35 NM southeast of pdx at 9000, nwbound landing at pdx. Upon crossing the boundary with ZSE I descended the aircraft to 7000. About a min later, I advised air carrier X of traffic 12 O'clock, 5 mi at 7800. Air carrier X was given a left turn and descent to 5500 ft and advised of the traffic again. Air carrier X accepted the clearance and responded that the aircraft was in sight. At that point I transferred air carrier X to the final controller. On that frequency, air carrier X reported that the traffic Y (VFR) that he had in sight above the cloud layer at approximately 7000 had spiraled down through the clouds in front of him. He spotted the aircraft Y upon breaking out at about 6500. I never had or could contact the (VFR) aircraft Y involved, and monitored it until losing radar contact at 2000 ft. I don't think that anything could have changed except the pilot of the VFR Y should have called for flight following or a clearance through the clouds.

Original NASA ASRS Text

Title: ACFT Y VFR IN IMC HAD LTSS WITH ACR X. PLTDEV.

Narrative: I WAS WORKING THE S AIRSPACE AT PORTLAND, OR, TRACON. ACR CHKED IN 35 NM SE OF PDX AT 9000, NWBOUND LNDG AT PDX. UPON XING THE BOUNDARY WITH ZSE I DSNDED THE ACFT TO 7000. ABOUT A MIN LATER, I ADVISED ACR X OF TFC 12 O'CLOCK, 5 MI AT 7800. ACR X WAS GIVEN A L TURN AND DSCNT TO 5500 FT AND ADVISED OF THE TFC AGAIN. ACR X ACCEPTED THE CLRNC AND RESPONDED THAT THE ACFT WAS IN SIGHT. AT THAT POINT I TRANSFERRED ACR X TO THE FINAL CTLR. ON THAT FREQ, ACR X RPTED THAT THE TFC Y (VFR) THAT HE HAD IN SIGHT ABOVE THE CLOUD LAYER AT APPROX 7000 HAD SPIRALED DOWN THROUGH THE CLOUDS IN FRONT OF HIM. HE SPOTTED THE ACFT Y UPON BREAKING OUT AT ABOUT 6500. I NEVER HAD OR COULD CONTACT THE (VFR) ACFT Y INVOLVED, AND MONITORED IT UNTIL LOSING RADAR CONTACT AT 2000 FT. I DON'T THINK THAT ANYTHING COULD HAVE CHANGED EXCEPT THE PLT OF THE VFR Y SHOULD HAVE CALLED FOR FLT FOLLOWING OR A CLRNC THROUGH THE CLOUDS.

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.