An airbus A319 flight crew descended below the procedures crossing altitude on arrival to lax.

Attributes
ACN	447404
Time
Date	199908
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : pdz.vor
State Reference	CA
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	A319
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival star : pdz.3
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer observation : company check pilot oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 260 flight time total : 8100 flight time type : 680
ASRS Report	447404
Person 2
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Descending and on arrival lax. Originally programmed for the civet arrival. That clearance was changed to the pdz arrival (pdz.pdz.3). The revised clearance was programmed into the FMC for runway 25R. When switched to the approach controller, we were told the runway would be runway 25L. The clearance to descend via the pdz arrival was never given, and if given, never heard or acknowledged. Approach frequency was so busy I could not break in to verify the descent. Descent clearance was received and initiated late. The FMC had to be reprogrammed for runway 25L and during the reprogramming process, automated flight system disengaged and reverted to open descent mode. The aircraft descended to 10000 ft -- 2000 ft below the 12000 ft crossing constraint at tejay. Contributors: 1) unclr and late clearance from approach controller. 2) revised clrncs requiring FMC flight plan modification at high workload phase of flight, ie, changing stars, runways. 3) socal approach needs to be aware of the impact on cockpit workload with the many changes during arrival. 4) PF was new captain on aircraft. I was check airman conducting IOE. I was heads down programming when reversion occurred.

Original NASA ASRS Text

Title: AN AIRBUS A319 FLC DSNDED BELOW THE PROCS XING ALT ON ARR TO LAX.

Narrative: DSNDING AND ON ARR LAX. ORIGINALLY PROGRAMMED FOR THE CIVET ARR. THAT CLRNC WAS CHANGED TO THE PDZ ARR (PDZ.PDZ.3). THE REVISED CLRNC WAS PROGRAMMED INTO THE FMC FOR RWY 25R. WHEN SWITCHED TO THE APCH CTLR, WE WERE TOLD THE RWY WOULD BE RWY 25L. THE CLRNC TO DSND VIA THE PDZ ARR WAS NEVER GIVEN, AND IF GIVEN, NEVER HEARD OR ACKNOWLEDGED. APCH FREQ WAS SO BUSY I COULD NOT BREAK IN TO VERIFY THE DSCNT. DSCNT CLRNC WAS RECEIVED AND INITIATED LATE. THE FMC HAD TO BE REPROGRAMMED FOR RWY 25L AND DURING THE REPROGRAMMING PROCESS, AUTOMATED FLT SYS DISENGAGED AND REVERTED TO OPEN DSCNT MODE. THE ACFT DSNDED TO 10000 FT -- 2000 FT BELOW THE 12000 FT XING CONSTRAINT AT TEJAY. CONTRIBUTORS: 1) UNCLR AND LATE CLRNC FROM APCH CTLR. 2) REVISED CLRNCS REQUIRING FMC FLT PLAN MODIFICATION AT HIGH WORKLOAD PHASE OF FLT, IE, CHANGING STARS, RWYS. 3) SOCAL APCH NEEDS TO BE AWARE OF THE IMPACT ON COCKPIT WORKLOAD WITH THE MANY CHANGES DURING ARR. 4) PF WAS NEW CAPT ON ACFT. I WAS CHK AIRMAN CONDUCTING IOE. I WAS HEADS DOWN PROGRAMMING WHEN REVERSION OCCURRED.

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.