Narrative:

En route from palm springs, ca, (psp) to burbank, ca, (bur). Approaching palmdale VOR (pmd), we were cleared to 'cross palmdale VOR at 12000, descend to cross janny (LYNXX6 arrival at bur) intersection at 8000.' both the first officer and I heard the clearance correctly, but he put 8000 ft in the altitude alerter. Approximately 4 NM east of pmd, the controller asked us to 'confirm you are at 12000.' at that point we were passing 11300 in the descent. Then she called opposing traffic at our 12 O'clock. I initiated an immediate climb back towards 12000, and the traffic passed off to our left, approximately 200 ft below and 1000 ft to the left of our aircraft.

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Original NASA ASRS Text

Title: CORP ACFT ON ARR DSNDS BELOW ASSIGNED. LTSS.

Narrative: ENRTE FROM PALM SPRINGS, CA, (PSP) TO BURBANK, CA, (BUR). APCHING PALMDALE VOR (PMD), WE WERE CLRED TO 'CROSS PALMDALE VOR AT 12000, DSND TO CROSS JANNY (LYNXX6 ARR AT BUR) INTXN AT 8000.' BOTH THE FO AND I HEARD THE CLRNC CORRECTLY, BUT HE PUT 8000 FT IN THE ALT ALERTER. APPROX 4 NM E OF PMD, THE CTLR ASKED US TO 'CONFIRM YOU ARE AT 12000.' AT THAT POINT WE WERE PASSING 11300 IN THE DSCNT. THEN SHE CALLED OPPOSING TFC AT OUR 12 O'CLOCK. I INITIATED AN IMMEDIATE CLB BACK TOWARDS 12000, AND THE TFC PASSED OFF TO OUR L, APPROX 200 FT BELOW AND 1000 FT TO THE L OF OUR ACFT.

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.