Air carrier X TCASII RA had near midair collision with VFR aircraft Y. Evasive action taken.

Attributes
ACN	223411
Time
Date	199210
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : vny
State Reference	CA
Altitude	msl bound lower : 3500 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bur
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent : approach
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft
Flight Phase	descent other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 7800 flight time type : 3800
ASRS Report	223411
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : nmac
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	faa : investigated
Miss Distance	horizontal : 0 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Air carrier X with a clearance to maintain 3500 until established on the localizer, cleared for the approach to runway 8. At or near silex intersection with first officer at the controls, I saw traffic on the TCASII and asked approach control if they were working that aircraft. Bur approach instructed us to climb to 4000 ft immediately. As the first officer established the climb the TCASII changed to an RA, directing a descent. At this time the aircraft Y was passing through 3800 ft and the first officer initiated a descent. At that time, I required a visual on a low wing single engine aircraft on a collision course with our aircraft. I initiated a very aggressive descent to avoid a collision. The clearance was between 100 and 200 ft as we passed vertical.

Original NASA ASRS Text

Title: ACR X TCASII RA HAD NMAC WITH VFR ACFT Y. EVASIVE ACTION TAKEN.

Narrative: ACR X WITH A CLRNC TO MAINTAIN 3500 UNTIL ESTABLISHED ON THE LOC, CLRED FOR THE APCH TO RWY 8. AT OR NEAR SILEX INTXN WITH FO AT THE CTLS, I SAW TFC ON THE TCASII AND ASKED APCH CTL IF THEY WERE WORKING THAT ACFT. BUR APCH INSTRUCTED US TO CLB TO 4000 FT IMMEDIATELY. AS THE FO ESTABLISHED THE CLB THE TCASII CHANGED TO AN RA, DIRECTING A DSCNT. AT THIS TIME THE ACFT Y WAS PASSING THROUGH 3800 FT AND THE FO INITIATED A DSCNT. AT THAT TIME, I REQUIRED A VISUAL ON A LOW WING SINGLE ENG ACFT ON A COLLISION COURSE WITH OUR ACFT. I INITIATED A VERY AGGRESSIVE DSCNT TO AVOID A COLLISION. THE CLRNC WAS BTWN 100 AND 200 FT AS WE PASSED VERT.

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.