TCASII resolves a conflict when an medium large transport was left on a vector too long.

Attributes
ACN	258152
Time
Date	199311
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bdf
State Reference	IL
Altitude	msl bound lower : 34000 msl bound upper : 35000
Environment
Flight Conditions	Marginal
Light	Night
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 5700 flight time type : 1734
ASRS Report	258152
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 120 flight time total : 5000 flight time type : 1000
ASRS Report	256801
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	faa : investigated
Miss Distance	horizontal : 18000 vertical : 1000
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Center had us descend from FL370 to FL350 and turn to 360 degree heading for vectors to the arrival at ord. At about XX20, we got a TCASII 'traffic, traffic' alert followed quickly by a 'descend, descend' TCASII command. About this time, ATC called us. We couldn't understand them because of the TCASII command. Then another aircraft came on frequency. The captain started a descent to FL340. I attempted to transmit our action -- 'descending now to FL340 for a TCASII command.' ATC acknowledged the descent and issued a turn to 090 degrees. We saw the TCASII traffic pass from 1 to 10 O'clock -- within 3 NM, according to our TCASII display. After the situation had stabilized, I asked center what he thought had just happened. He responded that he left us on our heading too long.

Original NASA ASRS Text

Title: TCASII RESOLVES A CONFLICT WHEN AN MLG WAS LEFT ON A VECTOR TOO LONG.

Narrative: CTR HAD US DSND FROM FL370 TO FL350 AND TURN TO 360 DEG HDG FOR VECTORS TO THE ARR AT ORD. AT ABOUT XX20, WE GOT A TCASII 'TFC, TFC' ALERT FOLLOWED QUICKLY BY A 'DSND, DSND' TCASII COMMAND. ABOUT THIS TIME, ATC CALLED US. WE COULDN'T UNDERSTAND THEM BECAUSE OF THE TCASII COMMAND. THEN ANOTHER ACFT CAME ON FREQ. THE CAPT STARTED A DSCNT TO FL340. I ATTEMPTED TO XMIT OUR ACTION -- 'DSNDING NOW TO FL340 FOR A TCASII COMMAND.' ATC ACKNOWLEDGED THE DSCNT AND ISSUED A TURN TO 090 DEGS. WE SAW THE TCASII TFC PASS FROM 1 TO 10 O'CLOCK -- WITHIN 3 NM, ACCORDING TO OUR TCASII DISPLAY. AFTER THE SIT HAD STABILIZED, I ASKED CTR WHAT HE THOUGHT HAD JUST HAPPENED. HE RESPONDED THAT HE LEFT US ON OUR HDG TOO LONG.

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.