DSCNT BELOW ASSIGNED ALT BY ACR. PLTDEV. POTENTIAL CONFLICT WITH MLT.

Narrative

WHILE WORKING AN AIR CARRIER ON AN ENRTE DSCNT TO BURBANK; I INSTRUCTED THE ACFT TO CROSS PALMDALE VOR AT 12000 CROSS JANNY INTXN AT 8000 FT. THE PLT READ BACK THE XING RESTRICTIONS VERBATIM. THE PMD XING RESTRICTION OF 12000 WAS ISSUED TO SEPARATE FROM AN OPPOSITE DIRECTION MLT AT 11000 FT. WHEN THE 2 ACFT WERE 5 MI APART THE AIR CARRIER WAS OBSERVED DSNDING BELOW 11000 FT EVEN THOUGH IT HAD NOT REACHED PMD VOR YET. TFC WAS ISSUED AND THE 2 ACFT PASSED WITHOUT INCIDENT. IN A CONVERSATION WITH THE PLT OF THE AIR CARRIER; HE ADVISED THAT WHILE HE WAS READING BACK THE XING RESTRICTIONS; HE WAS ALSO LOOKING AT LYNXX 6 ARR INTO BURBANK. THE LYNXX 6 ARR CHART ADVISES 'PLANNING INFO.' EXPECT TO CROSS PMD AT OR BELOW 13000 FT. ALTHOUGH THAT IS THE INSTRUCTION NORMALLY GIVEN; IT WAS NOT IN THIS INSTANCE. THE PLT ASSUMED THE PMD XING RESTRICTION TO BE 'AT OR BELOW 12000 FT'. LESSON LEARNED: CROSS 'AT' MEANS AT THE ALT; NOT ABOVE OR BELOW; REGARDLESS OF THE PUBLICATIONS. IF YOU HAVE ANY QUESTIONS; ASK DO NOT ASSUME. DO NOT ASSUME YOU WILL GET THE SAME INSTRUCTIONS AS ALWAYS FROM AIR TFC BECAUSE THE TFC SITUATION IS NEVER 'THE SAME AS BEFORE.'