B757 crew had poor ATC handling on the mitts 1 into lax.

Attributes
ACN	452130
Time
Date	199910
Day	Sun
Local Time Of Day	1801 To 2400
Place
State Reference	CA
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : vacating altitude
Route In Use	arrival star : mitts 1
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 5500 flight time type : 400
ASRS Report	452130
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne critical non adherence : published procedure non adherence : required legal separation non adherence : far
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took evasive action
Miss Distance	vertical : 500
Supplementary
Problem Areas	ATC Human Performance FAA
Primary Problem	FAA
Situations
ATC Facility	procedure or policy : sct.tracon
Airspace Structure	class e : sct.e

Narrative:

I read back clearance to cross snrkl at 12000 ft. At that time, I switched frequencys to company operations to order a wheelchair for a passenger. Upon returning back to approach frequency, I noticed 10000 ft set on the MCP. Captain told me we were cleared to lax from snrkl via the mitts one arrival. As we descended past snrkl from 12000 ft, I reported leaving 12000 ft for 10000 ft. At 11000 ft we got a TCASII warning 'climb, climb now' sounded. We looked at the TCASII display and saw traffic at our altitude on our nose. We never had a visual on it. We immediately stopped the descent until we were clear of conflict. That evening we were given 2 arrs and 4 runway changes inside of 90 mi from lax -- unacceptable. We called approach control via land line upon landing. They said we did nothing wrong. They were 'overloaded' and 'should have put airplanes in holding patterns' long before this situation ever developed.

Original NASA ASRS Text

Title: B757 CREW HAD POOR ATC HANDLING ON THE MITTS 1 INTO LAX.

Narrative: I READ BACK CLRNC TO CROSS SNRKL AT 12000 FT. AT THAT TIME, I SWITCHED FREQS TO COMPANY OPS TO ORDER A WHEELCHAIR FOR A PAX. UPON RETURNING BACK TO APCH FREQ, I NOTICED 10000 FT SET ON THE MCP. CAPT TOLD ME WE WERE CLRED TO LAX FROM SNRKL VIA THE MITTS ONE ARR. AS WE DSNDED PAST SNRKL FROM 12000 FT, I RPTED LEAVING 12000 FT FOR 10000 FT. AT 11000 FT WE GOT A TCASII WARNING 'CLB, CLB NOW' SOUNDED. WE LOOKED AT THE TCASII DISPLAY AND SAW TFC AT OUR ALT ON OUR NOSE. WE NEVER HAD A VISUAL ON IT. WE IMMEDIATELY STOPPED THE DSCNT UNTIL WE WERE CLR OF CONFLICT. THAT EVENING WE WERE GIVEN 2 ARRS AND 4 RWY CHANGES INSIDE OF 90 MI FROM LAX -- UNACCEPTABLE. WE CALLED APCH CTL VIA LAND LINE UPON LNDG. THEY SAID WE DID NOTHING WRONG. THEY WERE 'OVERLOADED' AND 'SHOULD HAVE PUT AIRPLANES IN HOLDING PATTERNS' LONG BEFORE THIS SIT EVER DEVELOPED.

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.