DC10 flight crew disputes sct multiple clrncs when challenged about descent altitude.

Attributes
ACN	458401
Time
Date	199912
Day	Wed
Local Time Of Day	0601 To 1200
Place
State Reference	CA
Altitude	msl bound lower : 10000 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 25l other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument precision arrival star : pdz
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : multi engine pilot : instrument pilot : atp
Experience	flight time last 90 days : 151 flight time total : 8850 flight time type : 764
ASRS Report	458401
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	non adherence : published procedure other anomaly other
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance
Consequence	faa : investigated faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance Airport Flight Crew Human Performance Airspace Structure
Primary Problem	ATC Human Performance

Narrative:

We were cleared to tnp and the pdz arrival into lax by ZLA and told to cross konzl at or above 17000 ft. Socal then told us to cross trtle at or above 16000 ft and then descend to 14000 ft. About 5 mi from pdz, we were given clock position 2 O'clock for brasilia that we were told we had a lot of overtake on. We were unable to see brasilia and were given its position again and also again told we had a lot of overtake on brasilia, which was going to north runways. At this time, about 2 mi from pdz, we were told to cross arnes at 10000 ft and maintain 250 KTS (we were at 340 KTS). We were unsure when socal wanted us to slow, so we asked 'when did you want us to slow to 250 KTS?' socal restated 'cross arnes at 10000 ft and maintain 250 KTS.' about 3 mi from arnes at 10000 ft and slowing to 250 KTS, socal said that our last clearance was to 12000 ft, but that we could remain at 10000 ft. We continued a landing at lax. I called socal on the landline and explained this sequence of events. I was told that we did exactly as instructed and that the controller was in error about our cleared altitude. I believe these types of arrs, with crossing restrs on them, cause lots of confusion. Why didn't socal clear us for the pdz 3 arrival rather than continually giving us altitudes that were essentially already on the arrival. I believe the socal controller was so concerned by the brasilia aircraft that she got confused as to what our clearance was. This is a very busy approach even without all the additional controller altitude clrncs.

Original NASA ASRS Text

Title: DC10 FLC DISPUTES SCT MULTIPLE CLRNCS WHEN CHALLENGED ABOUT DSCNT ALT.

Narrative: WE WERE CLRED TO TNP AND THE PDZ ARR INTO LAX BY ZLA AND TOLD TO CROSS KONZL AT OR ABOVE 17000 FT. SOCAL THEN TOLD US TO CROSS TRTLE AT OR ABOVE 16000 FT AND THEN DSND TO 14000 FT. ABOUT 5 MI FROM PDZ, WE WERE GIVEN CLOCK POS 2 O'CLOCK FOR BRASILIA THAT WE WERE TOLD WE HAD A LOT OF OVERTAKE ON. WE WERE UNABLE TO SEE BRASILIA AND WERE GIVEN ITS POS AGAIN AND ALSO AGAIN TOLD WE HAD A LOT OF OVERTAKE ON BRASILIA, WHICH WAS GOING TO N RWYS. AT THIS TIME, ABOUT 2 MI FROM PDZ, WE WERE TOLD TO CROSS ARNES AT 10000 FT AND MAINTAIN 250 KTS (WE WERE AT 340 KTS). WE WERE UNSURE WHEN SOCAL WANTED US TO SLOW, SO WE ASKED 'WHEN DID YOU WANT US TO SLOW TO 250 KTS?' SOCAL RESTATED 'CROSS ARNES AT 10000 FT AND MAINTAIN 250 KTS.' ABOUT 3 MI FROM ARNES AT 10000 FT AND SLOWING TO 250 KTS, SOCAL SAID THAT OUR LAST CLRNC WAS TO 12000 FT, BUT THAT WE COULD REMAIN AT 10000 FT. WE CONTINUED A LNDG AT LAX. I CALLED SOCAL ON THE LANDLINE AND EXPLAINED THIS SEQUENCE OF EVENTS. I WAS TOLD THAT WE DID EXACTLY AS INSTRUCTED AND THAT THE CTLR WAS IN ERROR ABOUT OUR CLRED ALT. I BELIEVE THESE TYPES OF ARRS, WITH XING RESTRS ON THEM, CAUSE LOTS OF CONFUSION. WHY DIDN'T SOCAL CLR US FOR THE PDZ 3 ARR RATHER THAN CONTINUALLY GIVING US ALTS THAT WERE ESSENTIALLY ALREADY ON THE ARR. I BELIEVE THE SOCAL CTLR WAS SO CONCERNED BY THE BRASILIA ACFT THAT SHE GOT CONFUSED AS TO WHAT OUR CLRNC WAS. THIS IS A VERY BUSY APCH EVEN WITHOUT ALL THE ADDITIONAL CTLR ALT CLRNCS.

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.