Narrative:

The first officer was flying and began descent on the kepec RNAV 1 arrival. Our cruise altitude was FL230 which can be too low to receive terminal information (ATIS). Just prior to our descent, I (captain) informed the first officer that I was going off the ATC radio to get the terminal information (ATIS, gate, etc). While I was receiving information, the first officer received descent instructions from las approach to 'descend via the kepec 1 arrival.' the first officer then put 8000 ft in the FCU window, which was our clearance limit, and began an 'open descent.' an open descent on the airbus will not meet altitude restrs for the RNAV arrival. When I returned to the ATC radio frequency, the first officer stated we were cleared to 8000 ft. I asked if we received a 'descend via' clearance, and he seemed somewhat confused. I immediately stopped the aircraft descent which had already gone through the first altitude restr, and returned to the proper altitude for our location. We had deviated approximately 2000 ft lower than allowed. We received no ATC inquiry of our altitude deviation. No other conflicting traffic was near. Flight then proceeded normally at the correct altitudes. This is an age old problem in aviation. It's why we need at least 2 crew members in the cockpit. It would help if las ATIS could be received at a greater distance from the airport. The descent phase of flight is not a good time to be off the ATC radio receiving terminal information.

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Original NASA ASRS Text

Title: A320 FLT CREW DEVIATES FROM PUBLISHED ALT RESTR ON RNAV ARR TO LAS.

Narrative: THE FO WAS FLYING AND BEGAN DSCNT ON THE KEPEC RNAV 1 ARR. OUR CRUISE ALT WAS FL230 WHICH CAN BE TOO LOW TO RECEIVE TERMINAL INFO (ATIS). JUST PRIOR TO OUR DSCNT, I (CAPT) INFORMED THE FO THAT I WAS GOING OFF THE ATC RADIO TO GET THE TERMINAL INFO (ATIS, GATE, ETC). WHILE I WAS RECEIVING INFO, THE FO RECEIVED DSCNT INSTRUCTIONS FROM LAS APCH TO 'DSND VIA THE KEPEC 1 ARR.' THE FO THEN PUT 8000 FT IN THE FCU WINDOW, WHICH WAS OUR CLRNC LIMIT, AND BEGAN AN 'OPEN DSCNT.' AN OPEN DSCNT ON THE AIRBUS WILL NOT MEET ALT RESTRS FOR THE RNAV ARR. WHEN I RETURNED TO THE ATC RADIO FREQ, THE FO STATED WE WERE CLRED TO 8000 FT. I ASKED IF WE RECEIVED A 'DSND VIA' CLRNC, AND HE SEEMED SOMEWHAT CONFUSED. I IMMEDIATELY STOPPED THE ACFT DSCNT WHICH HAD ALREADY GONE THROUGH THE FIRST ALT RESTR, AND RETURNED TO THE PROPER ALT FOR OUR LOCATION. WE HAD DEVIATED APPROX 2000 FT LOWER THAN ALLOWED. WE RECEIVED NO ATC INQUIRY OF OUR ALTDEV. NO OTHER CONFLICTING TFC WAS NEAR. FLT THEN PROCEEDED NORMALLY AT THE CORRECT ALTS. THIS IS AN AGE OLD PROB IN AVIATION. IT'S WHY WE NEED AT LEAST 2 CREW MEMBERS IN THE COCKPIT. IT WOULD HELP IF LAS ATIS COULD BE RECEIVED AT A GREATER DISTANCE FROM THE ARPT. THE DSCNT PHASE OF FLT IS NOT A GOOD TIME TO BE OFF THE ATC RADIO RECEIVING TERMINAL INFO.

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.