Air carrier descending has TCASII alert of same altitude traffic. Hurried descent.

Attributes
ACN	199782
Time
Date	199201
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lax
State Reference	CA
Altitude	msl bound lower : 20000 msl bound upper : 21000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
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 : 14837 flight time type : 290
ASRS Report	199782
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 210 flight time total : 5000 flight time type : 490
ASRS Report	199887
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The event occurred on flight from slc to lax aboard an large transport inbound to lax. The WX was clear. We were cleared to 14000 ft with instructions to expedite the descent. As we approached civit intersection on the lax approach, the TCASII alerted us of another aircraft 2 1/2 mi north of our position at 21000 ft as we descended through 21000 ft. We located the aircraft visually and hurried our descent through 20000 ft.

Original NASA ASRS Text

Title: ACR DSNDING HAS TCASII ALERT OF SAME ALT TFC. HURRIED DSCNT.

Narrative: THE EVENT OCCURRED ON FLT FROM SLC TO LAX ABOARD AN LGT INBOUND TO LAX. THE WX WAS CLR. WE WERE CLRED TO 14000 FT WITH INSTRUCTIONS TO EXPEDITE THE DSCNT. AS WE APCHED CIVIT INTXN ON THE LAX APCH, THE TCASII ALERTED US OF ANOTHER ACFT 2 1/2 MI N OF OUR POS AT 21000 FT AS WE DSNDED THROUGH 21000 FT. WE LOCATED THE ACFT VISUALLY AND HURRIED OUR DSCNT THROUGH 20000 FT.

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.