Close proximity commuter mdt being vectored for ILS 23R at rdu and unknown aircraft in the area.

Attributes
ACN	198401
Time
Date	199201
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rdu
State Reference	NC
Altitude	msl bound lower : 4700 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : rdu
Operator	common carrier : air carrier
Make Model Name	Medium Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 5800 flight time type : 500
ASRS Report	198401
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Flight mdt to rdu at 5000 ft heading 140 degrees. Radar vector for ILS 23R at rdu. ATC clearance 'turn right heading 210 degrees to join 23R localizer descend to 2200 ft.' as we started the turn we got a TCASII alert, the traffic was 3 O'clock and 2 mi. Reply 'we are unable to accept 210 degrees due to traffic.' ATC 'turn left heading 360 degrees.' at the time of the alert the traffic was at 4700 ft, we were at 5000 ft descending. We started left then back to the right heading 240 degrees to join 23R localizer, then 260 degrees to join 23R localizer, as cleared by ATC. At the assigned speed of 190 KTS we would have caught the traffic in the turn. This traffic was never reported to us by ATC.

Original NASA ASRS Text

Title: CLOSE PROX COMMUTER MDT BEING VECTORED FOR ILS 23R AT RDU AND UNKNOWN ACFT IN THE AREA.

Narrative: FLT MDT TO RDU AT 5000 FT HDG 140 DEGS. RADAR VECTOR FOR ILS 23R AT RDU. ATC CLRNC 'TURN R HDG 210 DEGS TO JOIN 23R LOC DSND TO 2200 FT.' AS WE STARTED THE TURN WE GOT A TCASII ALERT, THE TFC WAS 3 O'CLOCK AND 2 MI. REPLY 'WE ARE UNABLE TO ACCEPT 210 DEGS DUE TO TFC.' ATC 'TURN L HDG 360 DEGS.' AT THE TIME OF THE ALERT THE TFC WAS AT 4700 FT, WE WERE AT 5000 FT DSNDING. WE STARTED L THEN BACK TO THE R HDG 240 DEGS TO JOIN 23R LOC, THEN 260 DEGS TO JOIN 23R LOC, AS CLRED BY ATC. AT THE ASSIGNED SPD OF 190 KTS WE WOULD HAVE CAUGHT THE TFC IN THE TURN. THIS TFC WAS NEVER RPTED TO US BY ATC.

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.