Narrative:

ZLA cleared us 'direct konzl, flight plan route (tnp, pdz 3, lax) after passing tnp VOR.' subsequently issued clearance to 'cross konzl at 17000 ft.' all was fine up until we passed konzl. ZLA then switched us to approach. Captain had been busy with approach checklist and FMS, but immediately switched frequencys. Meanwhile, I, believing we were cleared on the pdz 3 arrival and finding us just 4 mi from the next fix (trtle), began a descent to comply with the 'cross at 16000 ft' restr published on the chart. Approach then queried us as to our altitude, which at that point was 16400 ft. Captain replied that we were descending on the pdz 3. Controller stated that we were never cleared for the pdz 3, but immediately issued such clearance. Controller then gave us a revised runway, quickly followed by 2 speed restrs. Captain became immersed in FMS (normal in such situation) and slowing down/going down became a problem. A misunderstood and ambiguous clearance, coupled with center's and approach's failure to provide timely instructions contributed. They can't reasonably expect us to comply with an altitude restr 4 mi from the fix at 320 KIAS, with clearance still pending. (Too many last min changes at lax. We always manage to comply, but it's hardly ever pretty!) add to the mix a 12 1/2 hour duty day and even 2 very experienced pilots are quickly buried!

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Original NASA ASRS Text

Title: AN A320 FO RPT ON A CLRNC MISUNDERSTANDING WHILE IN DSCNT ON THE PDZ 3 ARR INTO LAX, CA.

Narrative: ZLA CLRED US 'DIRECT KONZL, FLT PLAN RTE (TNP, PDZ 3, LAX) AFTER PASSING TNP VOR.' SUBSEQUENTLY ISSUED CLRNC TO 'CROSS KONZL AT 17000 FT.' ALL WAS FINE UP UNTIL WE PASSED KONZL. ZLA THEN SWITCHED US TO APCH. CAPT HAD BEEN BUSY WITH APCH CHKLIST AND FMS, BUT IMMEDIATELY SWITCHED FREQS. MEANWHILE, I, BELIEVING WE WERE CLRED ON THE PDZ 3 ARR AND FINDING US JUST 4 MI FROM THE NEXT FIX (TRTLE), BEGAN A DSCNT TO COMPLY WITH THE 'CROSS AT 16000 FT' RESTR PUBLISHED ON THE CHART. APCH THEN QUERIED US AS TO OUR ALT, WHICH AT THAT POINT WAS 16400 FT. CAPT REPLIED THAT WE WERE DSNDING ON THE PDZ 3. CTLR STATED THAT WE WERE NEVER CLRED FOR THE PDZ 3, BUT IMMEDIATELY ISSUED SUCH CLRNC. CTLR THEN GAVE US A REVISED RWY, QUICKLY FOLLOWED BY 2 SPD RESTRS. CAPT BECAME IMMERSED IN FMS (NORMAL IN SUCH SIT) AND SLOWING DOWN/GOING DOWN BECAME A PROB. A MISUNDERSTOOD AND AMBIGUOUS CLRNC, COUPLED WITH CTR'S AND APCH'S FAILURE TO PROVIDE TIMELY INSTRUCTIONS CONTRIBUTED. THEY CAN'T REASONABLY EXPECT US TO COMPLY WITH AN ALT RESTR 4 MI FROM THE FIX AT 320 KIAS, WITH CLRNC STILL PENDING. (TOO MANY LAST MIN CHANGES AT LAX. WE ALWAYS MANAGE TO COMPLY, BUT IT'S HARDLY EVER PRETTY!) ADD TO THE MIX A 12 1/2 HR DUTY DAY AND EVEN 2 VERY EXPERIENCED PLTS ARE QUICKLY BURIED!

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.