Narrative:

Descending from las vegas, to los angeles, ca, we were cleared for the civet two profile descent to maintain 320 KTS before civet intersection. Shortly after this clearance we were told to slow to 280 KTS. The aircraft ahead of us on the same profile, questioned ATC about the speed across arnes intersection. ATC told him to delete the speed restriction over arnes. After this, ATC asked us what is our speed, I replied 280 KTS assigned. The controller said that we should of been at 320 KTS and that 280 KTS was given to another aircraft. We increased speed to 320 KTS. Approaching 18000' I finished the descent checklist and told the captain that I would be off the radio to call company. I called lax ramp control and obtained gate number and gave them our ETA at gate. Coming back on radio I noticed we had leveled at 14000' which is normal outside of civet. We were approximately 55 mi from lax. Civet is 52 mi out. At civet we continued descent to cross arnes at 10000'. At approximately 12000' ATC asked us what was our altitude. I replied 12000'. Unknown to me, we had received an amended clearance earlier to maintain 14000'. Possible causes of altitude deviation. I was not listening to ATC when an amended clearance was given. Company report of ETA and gate assignment are not as important as both pilots listening to ATC in a high traffic area on a two man crew aircraft. ATC changing instructions too many times in one profile. ATC trying to handle too many aircraft at one time with the minimum sep at too many different speeds deviating from normal profile speeds. Supplemental information from acn 143962. I was cleared for the civet profile descent to maintain 310 KTS or greater before civet, then told and answered to reduce to 280 KTS still before civet, then given a clearance to cancel the civet profile and to maintain 14000'.

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Original NASA ASRS Text

Title: ACR MLG SPEED DEVIATION IN RESPONSE TO WRONG CALLSIGN THEN ALT DEVIATION AS PIC CONTINUED WITH STAR RESTRICTIONS AFTER BEING TOLD TO MAINTAIN AN ALT.

Narrative: DSNDING FROM LAS VEGAS, TO LOS ANGELES, CA, WE WERE CLRED FOR THE CIVET TWO PROFILE DSNT TO MAINTAIN 320 KTS BEFORE CIVET INTXN. SHORTLY AFTER THIS CLRNC WE WERE TOLD TO SLOW TO 280 KTS. THE ACFT AHEAD OF US ON THE SAME PROFILE, QUESTIONED ATC ABOUT THE SPD ACROSS ARNES INTXN. ATC TOLD HIM TO DELETE THE SPD RESTRICTION OVER ARNES. AFTER THIS, ATC ASKED US WHAT IS OUR SPD, I REPLIED 280 KTS ASSIGNED. THE CTLR SAID THAT WE SHOULD OF BEEN AT 320 KTS AND THAT 280 KTS WAS GIVEN TO ANOTHER ACFT. WE INCREASED SPD TO 320 KTS. APCHING 18000' I FINISHED THE DSNT CHKLIST AND TOLD THE CAPT THAT I WOULD BE OFF THE RADIO TO CALL COMPANY. I CALLED LAX RAMP CTL AND OBTAINED GATE NUMBER AND GAVE THEM OUR ETA AT GATE. COMING BACK ON RADIO I NOTICED WE HAD LEVELED AT 14000' WHICH IS NORMAL OUTSIDE OF CIVET. WE WERE APPROX 55 MI FROM LAX. CIVET IS 52 MI OUT. AT CIVET WE CONTINUED DSNT TO CROSS ARNES AT 10000'. AT APPROX 12000' ATC ASKED US WHAT WAS OUR ALT. I REPLIED 12000'. UNKNOWN TO ME, WE HAD RECEIVED AN AMENDED CLRNC EARLIER TO MAINTAIN 14000'. POSSIBLE CAUSES OF ALT DEV. I WAS NOT LISTENING TO ATC WHEN AN AMENDED CLRNC WAS GIVEN. COMPANY RPT OF ETA AND GATE ASSIGNMENT ARE NOT AS IMPORTANT AS BOTH PLTS LISTENING TO ATC IN A HIGH TFC AREA ON A TWO MAN CREW ACFT. ATC CHANGING INSTRUCTIONS TOO MANY TIMES IN ONE PROFILE. ATC TRYING TO HANDLE TOO MANY ACFT AT ONE TIME WITH THE MINIMUM SEP AT TOO MANY DIFFERENT SPDS DEVIATING FROM NORMAL PROFILE SPDS. SUPPLEMENTAL INFO FROM ACN 143962. I WAS CLRED FOR THE CIVET PROFILE DSNT TO MAINTAIN 310 KTS OR GREATER BEFORE CIVET, THEN TOLD AND ANSWERED TO REDUCE TO 280 KTS STILL BEFORE CIVET, THEN GIVEN A CLRNC TO CANCEL THE CIVET PROFILE AND TO MAINTAIN 14000'.

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.