Medium large transport on IFR approach told of conflict alert indication by center.

Attributes
ACN	81303
Time
Date	198802
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zla
State Reference	CA
Altitude	msl bound lower : 11500 msl bound upper : 11500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport
Navigation In Use	Other
Flight Phase	descent other
Route In Use	arrival : profile descent arrival other enroute airway : zla
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 16000
ASRS Report	81303
Person 2
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : far
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Miss Distance	vertical : 200
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Lax ARTCC advised medium large transport, 'I have a ca, maintain your altitude. Just popped up conflicting traffic at 11500'.' we were at 11700'. First officer was flying and immediately pushed altitude hold. Aircraft leveled off at 11500'. The air traffic controller kept us informed of our situation as we climbed up to 12200'. All of this took less than 20 seconds when the controller advised us we were clear of traffic. Suggestion: install collision avoidance on board aircraft.

Original NASA ASRS Text

Title: MLG ON IFR APCH TOLD OF CONFLICT ALERT INDICATION BY CENTER.

Narrative: LAX ARTCC ADVISED MLG, 'I HAVE A CA, MAINTAIN YOUR ALT. JUST POPPED UP CONFLICTING TFC AT 11500'.' WE WERE AT 11700'. F/O WAS FLYING AND IMMEDIATELY PUSHED ALT HOLD. ACFT LEVELED OFF AT 11500'. THE AIR TFC CTLR KEPT US INFORMED OF OUR SITUATION AS WE CLBED UP TO 12200'. ALL OF THIS TOOK LESS THAN 20 SECS WHEN THE CTLR ADVISED US WE WERE CLR OF TFC. SUGGESTION: INSTALL COLLISION AVOIDANCE ON BOARD ACFT.

Data retrieved from NASA's ASRS site as of August 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.