Air carrier has close proximity with small aircraft. TCASII RA.

Attributes
ACN	221978
Time
Date	199209
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : rdu
State Reference	NC
Altitude	msl bound lower : 5500 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : rdu artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 250 flight time total : 7000 flight time type : 700
ASRS Report	221978
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

While being radar vectored for ILS 5L at rdu we were cleared to descend to 4000 ft MSL, traffic was right to left VFR, small GA aircraft reported by ATC at 5500 ft MSL. Suddenly 5500 ft traffic made an unexpected left turn, off assigned heading. TCASII gave us an RA -- basically telling us to maintain our current rate of descent (+/- 1200 FPM). TCASII worked well.

Original NASA ASRS Text

Title: ACR HAS CLOSE PROX WITH SMA. TCASII RA.

Narrative: WHILE BEING RADAR VECTORED FOR ILS 5L AT RDU WE WERE CLRED TO DSND TO 4000 FT MSL, TFC WAS R TO L VFR, SMALL GA ACFT RPTED BY ATC AT 5500 FT MSL. SUDDENLY 5500 FT TFC MADE AN UNEXPECTED L TURN, OFF ASSIGNED HDG. TCASII GAVE US AN RA -- BASICALLY TELLING US TO MAINTAIN OUR CURRENT RATE OF DSCNT (+/- 1200 FPM). TCASII WORKED WELL.

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.