Air carrier X TCASII RA with VFR aircraft Y. See and avoid concept. Evasive action taken.

Attributes
ACN	273888
Time
Date	199405
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bdl
State Reference	CT
Altitude	msl bound lower : 8500 msl bound upper : 8500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bdl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	273888
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Air carrier X was approximately 35 mi northwest of bdl and I issued a descent from 11000 ft to 5000 ft (after scanning to observe no traffic in area) and a turn for the downwind (aircraft arriving bdl). Meanwhile, my attns were distracted giving a position relief briefing and by a VFR arrival making a rapid descent to bdl. There was a fast moving unidented VFR aircraft, Y, at 8500 ft moving nwbound into the path of the VFR arrival. I got the VFR arrival turned to avoid the unidented Y and I moved my scan to air carrier X, which in my mind should have been below the 8500 ft traffic by this time. Air carrier X was just descending through 9000 ft and converging with the 8500 ft VFR Y. I immediately issued a turn to avoid the traffic, but by that time the pilot had already received the TCASII advisory to climb.

Original NASA ASRS Text

Title: ACR X TCASII RA WITH VFR ACFT Y. SEE AND AVOID CONCEPT. EVASIVE ACTION TAKEN.

Narrative: ACR X WAS APPROX 35 MI NW OF BDL AND I ISSUED A DSCNT FROM 11000 FT TO 5000 FT (AFTER SCANNING TO OBSERVE NO TFC IN AREA) AND A TURN FOR THE DOWNWIND (ACFT ARRIVING BDL). MEANWHILE, MY ATTNS WERE DISTRACTED GIVING A POS RELIEF BRIEFING AND BY A VFR ARR MAKING A RAPID DSCNT TO BDL. THERE WAS A FAST MOVING UNIDENTED VFR ACFT, Y, AT 8500 FT MOVING NWBOUND INTO THE PATH OF THE VFR ARR. I GOT THE VFR ARR TURNED TO AVOID THE UNIDENTED Y AND I MOVED MY SCAN TO ACR X, WHICH IN MY MIND SHOULD HAVE BEEN BELOW THE 8500 FT TFC BY THIS TIME. ACR X WAS JUST DSNDING THROUGH 9000 FT AND CONVERGING WITH THE 8500 FT VFR Y. I IMMEDIATELY ISSUED A TURN TO AVOID THE TFC, BUT BY THAT TIME THE PLT HAD ALREADY RECEIVED THE TCASII ADVISORY TO CLB.

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.