Narrative:

Our flight was advised that we had descended incorrectly to cross civet intersection. The clearance was understood and is believed to have been read back, 'descend and maintain 10000', cross civet at or below 14000'.' civet was crossed between 13000 and 14000', at which point the controller's comment was, 'a little low over civet.' he said that the clearance was, 'descend and maintain 10000, cross civet at or above 14000.' we inquired if there had been any traffic conflict. He said 'no.' also, the MEA is 10500', so terrain was not a factor. Factors believed to have caused this: inappropriate hearback, inappropriate readback, expectation of clearance (clearance similar to profile descent commonly used), crew fatigue (logged approximately 8 hours flight time at this point, biological time early a.M.), and PNF was off frequency. Corrective action: the clearance itself seems unusual if not unsafe, as well as being confusing. I'm not accustomed to being cleared to cross a fix at or above an altitude with clearance to a lower altitude. A less confusing alternative might be to simply clear an aircraft to cross a fix at or above an altitude. Once at that fix, clear the aircraft to the lower altitude.

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Original NASA ASRS Text

Title: FLT CREW OF MLG ON DOWNE 3 ARR AT LAX ALLEGEDLY LOW AT CIVET INTXN.

Narrative: OUR FLT WAS ADVISED THAT WE HAD DSNDED INCORRECTLY TO CROSS CIVET INTXN. THE CLRNC WAS UNDERSTOOD AND IS BELIEVED TO HAVE BEEN READ BACK, 'DSND AND MAINTAIN 10000', CROSS CIVET AT OR BELOW 14000'.' CIVET WAS CROSSED BTWN 13000 AND 14000', AT WHICH POINT THE CTLR'S COMMENT WAS, 'A LITTLE LOW OVER CIVET.' HE SAID THAT THE CLRNC WAS, 'DSND AND MAINTAIN 10000, CROSS CIVET AT OR ABOVE 14000.' WE INQUIRED IF THERE HAD BEEN ANY TFC CONFLICT. HE SAID 'NO.' ALSO, THE MEA IS 10500', SO TERRAIN WAS NOT A FACTOR. FACTORS BELIEVED TO HAVE CAUSED THIS: INAPPROPRIATE HEARBACK, INAPPROPRIATE READBACK, EXPECTATION OF CLRNC (CLRNC SIMILAR TO PROFILE DSNT COMMONLY USED), CREW FATIGUE (LOGGED APPROX 8 HRS FLT TIME AT THIS POINT, BIOLOGICAL TIME EARLY A.M.), AND PNF WAS OFF FREQ. CORRECTIVE ACTION: THE CLRNC ITSELF SEEMS UNUSUAL IF NOT UNSAFE, AS WELL AS BEING CONFUSING. I'M NOT ACCUSTOMED TO BEING CLRED TO CROSS A FIX AT OR ABOVE AN ALT WITH CLRNC TO A LOWER ALT. A LESS CONFUSING ALTERNATIVE MIGHT BE TO SIMPLY CLR AN ACFT TO CROSS A FIX AT OR ABOVE AN ALT. ONCE AT THAT FIX, CLR THE ACFT TO THE LOWER ALT.

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.