An IFR aircraft came very, very close to a VFR aircraft.

Attributes
ACN	158547
Time
Date	199009
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : psb
State Reference	PA
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Route In Use	enroute airway : zny
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 7
ASRS Report	158547
Person 2
Affiliation	government : faa
Function	controller : handoff position
Qualification	controller : radar
Experience	controller military : 3 controller radar : 21
ASRS Report	157720
Events
Anomaly	conflict : nmac non adherence : far other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : unable other
Consequence	Other
Miss Distance	vertical : 10
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Small aircraft level 8000' on IFR flight plan in VFR conditions. I issued the aircraft VFR traffic 12-1 O'clock and 5 mi indicating 8000'. Received no response. Called small aircraft 3 additional times to establish communications, no response. Made attempt to find what frequency small aircraft was on. Issued traffic alert, no response. Called aircraft again, no response. Small aircraft checked on my frequency after passing the other aircraft. The VFR aircraft remained at 8000' across my sector and was observed descending in the vicinity of perkiomen valley airport.

Original NASA ASRS Text

Title: AN IFR ACFT CAME VERY, VERY CLOSE TO A VFR ACFT.

Narrative: SMA LEVEL 8000' ON IFR FLT PLAN IN VFR CONDITIONS. I ISSUED THE ACFT VFR TFC 12-1 O'CLOCK AND 5 MI INDICATING 8000'. RECEIVED NO RESPONSE. CALLED SMA 3 ADDITIONAL TIMES TO ESTABLISH COMS, NO RESPONSE. MADE ATTEMPT TO FIND WHAT FREQ SMA WAS ON. ISSUED TFC ALERT, NO RESPONSE. CALLED ACFT AGAIN, NO RESPONSE. SMA CHKED ON MY FREQ AFTER PASSING THE OTHER ACFT. THE VFR ACFT REMAINED AT 8000' ACROSS MY SECTOR AND WAS OBSERVED DSNDING IN THE VICINITY OF PERKIOMEN VALLEY ARPT.

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.