Atx X TCASII RA with VFR aircraft in IMC. Evasive action taken. Pilot deviation.

Attributes
ACN	287714
Time
Date	199411
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ste
State Reference	WI
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp
Operator	common carrier : air taxi
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 135
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 3
ASRS Report	287714
Person 2
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : far non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 500 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Atx X was inbound to cwa from the south and was cleared for the VOR DME runway 35 approach via over ste. Aircraft was in marginal radar coverage when it reported and executed a TCASII maneuver. The IFR aircraft reported the maneuver and stated that he thought the other aircraft was in the clouds. Aircraft were in an area of known non-radar, but after the maneuver was complete, the VFR aircraft Y was in close proximity to the IFR aircraft. The pilot reported that the TCASII saved a hit in the clouds. In this case I would agree. The aircraft were unseen and in very close proximity.

Original NASA ASRS Text

Title: ATX X TCASII RA WITH VFR ACFT IN IMC. EVASIVE ACTION TAKEN. PLTDEV.

Narrative: ATX X WAS INBOUND TO CWA FROM THE S AND WAS CLRED FOR THE VOR DME RWY 35 APCH VIA OVER STE. ACFT WAS IN MARGINAL RADAR COVERAGE WHEN IT RPTED AND EXECUTED A TCASII MANEUVER. THE IFR ACFT RPTED THE MANEUVER AND STATED THAT HE THOUGHT THE OTHER ACFT WAS IN THE CLOUDS. ACFT WERE IN AN AREA OF KNOWN NON-RADAR, BUT AFTER THE MANEUVER WAS COMPLETE, THE VFR ACFT Y WAS IN CLOSE PROX TO THE IFR ACFT. THE PLT RPTED THAT THE TCASII SAVED A HIT IN THE CLOUDS. IN THIS CASE I WOULD AGREE. THE ACFT WERE UNSEEN AND IN VERY CLOSE PROX.

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.