Small aircraft Y VFR in IMC had conflict with cpr X. Pilot deviation.

Attributes
ACN	181177
Time
Date	199106
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gee
State Reference	NY
Altitude	msl bound lower : 4500 msl bound upper : 4500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Small Transport
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : roc
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute : direct
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	181177
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe inflight encounter : vfr in imc non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Cpr X was descending northbound from 11000 to 4000 to land at rochester, ny. Traffic was issued 12 O'clock 6 mi northbound VFR at 4500. Traffic issued 3 times. The third time it was issued as 'just off your left, less than 1 mi'. Cpr X was descending through 4700 and said he had the traffic in sight. Targets did not merge and no evasive action was taken. I never issued a 'traffic alert'. After cpr X landed, the pilot called and told us the traffic had been an small aircraft Y in the clouds. He had assumed the altitude was incorrect. The planes passed from 1/4 to 1/2 mi from each other. Cpr X assumed the traffic would be no factor during an IMC descent. I had no way of telling if VFR traffic was in VFR of IFR conditions. I assumed the traffic was in VFR conditions and cpr X was in a VMC descent. The pilot wanted to know who the traffic was. Had he mentioned it as soon as it happened, I could have started an ARTS target and had the computer track small aircraft Y. By waiting, we cannot prove who the aircraft actually was. Both pilots and controllers need to talk to each other more. I did not know cpr X was IMC and that a near miss occurred until 10-15 mins after the incident. We need to both realize that some pilots don't follow the rules

Original NASA ASRS Text

Title: SMA Y VFR IN IMC HAD CONFLICT WITH CPR X. PLTDEV.

Narrative: CPR X WAS DSNDING NBOUND FROM 11000 TO 4000 TO LAND AT ROCHESTER, NY. TFC WAS ISSUED 12 O'CLOCK 6 MI NBOUND VFR AT 4500. TFC ISSUED 3 TIMES. THE THIRD TIME IT WAS ISSUED AS 'JUST OFF YOUR L, LESS THAN 1 MI'. CPR X WAS DSNDING THROUGH 4700 AND SAID HE HAD THE TFC IN SIGHT. TARGETS DID NOT MERGE AND NO EVASIVE ACTION WAS TAKEN. I NEVER ISSUED A 'TFC ALERT'. AFTER CPR X LANDED, THE PLT CALLED AND TOLD US THE TFC HAD BEEN AN SMA Y IN THE CLOUDS. HE HAD ASSUMED THE ALT WAS INCORRECT. THE PLANES PASSED FROM 1/4 TO 1/2 MI FROM EACH OTHER. CPR X ASSUMED THE TFC WOULD BE NO FACTOR DURING AN IMC DSCNT. I HAD NO WAY OF TELLING IF VFR TFC WAS IN VFR OF IFR CONDITIONS. I ASSUMED THE TFC WAS IN VFR CONDITIONS AND CPR X WAS IN A VMC DSCNT. THE PLT WANTED TO KNOW WHO THE TFC WAS. HAD HE MENTIONED IT AS SOON AS IT HAPPENED, I COULD HAVE STARTED AN ARTS TARGET AND HAD THE COMPUTER TRACK SMA Y. BY WAITING, WE CANNOT PROVE WHO THE ACFT ACTUALLY WAS. BOTH PLTS AND CTLRS NEED TO TALK TO EACH OTHER MORE. I DID NOT KNOW CPR X WAS IMC AND THAT A NEAR MISS OCCURRED UNTIL 10-15 MINS AFTER THE INCIDENT. WE NEED TO BOTH REALIZE THAT SOME PLTS DON'T FOLLOW THE RULES

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.