Narrative:

During cruise flight (atl to msy) ZME (134.92) issued a descent crossing restr to wit: 'cross 115 NM north of harvey VOR at FL280' which we acknowledged and continued to maintain FL350. With fuel conservation in mind, I waited until I was approximately 15-18 mi from the crossing restr (harvey VOR 115 DME) to initiate an idle power descent. Shortly thereafter, ZME instructed us to 'descend to FL310,' saying nothing further, which we interpreted to mean that he is concerned that we might not make our crossing restr 115 NM north of harvey VOR at FL280. The controller at this point is very busy with other radio calls and we are descending at 3000 FPM. While approaching FL290, he requests our altitude and we respond 'approaching FL290,' to which he replies, 'maintain FL290' and that we were supposed to have maintained FL310. I told him that we meeting our descent requirements in order to comply with his previous clearance for the crossing restr and that he had never negated that clearance by instructing us to 'delete previous restr to cross 115 mi north of harvey at FL280' or any words other than to 'descend to FL310.' I told center that we never received nor had we acknowledged an amendment or cancellation of his crossing restr clearance to which he responded 'well somebody did!' this is the second time this yr I have descended to an altitude based upon a crossing restr by center, only to have center change (apparently) its mind and not cancel/negate the descent clearance in standard, easily understood radio phraseology. I queried the copilot on all aspects of this event and his interpretation of all radio calls and actions were the same as mine. Center controllers nor we cannot permit traffic volume/radio calls to come before clear, concise radio phraseology so that there is no possible misinterp as to what the other means or expects. Callback conversation with reporter revealed the following information: reporter was called and counseled to assure he had a proper understanding of ARTCC phraseology and how an altitude assigned changes any previous clrncs. Reporter and his first officer were positive the controller altitude assignment was an encouragement to begin descent and not a restr. At least he was proud of the fact that he inquired of the first officer and they were in agreement of what the new clearance meant to them. Reporter was counseled that any time a new altitude is issued to him that it was now a mandatory clearance to supersede any previous clearance. Reporter expressed thanks for being enlightened and would spread the word to other flight crew so all may have a proper understanding of such procedures.

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Original NASA ASRS Text

Title: FLC FAILS TO UNDERSTAND ARTCC INSTRUCTIONS.

Narrative: DURING CRUISE FLT (ATL TO MSY) ZME (134.92) ISSUED A DSCNT XING RESTR TO WIT: 'CROSS 115 NM N OF HARVEY VOR AT FL280' WHICH WE ACKNOWLEDGED AND CONTINUED TO MAINTAIN FL350. WITH FUEL CONSERVATION IN MIND, I WAITED UNTIL I WAS APPROX 15-18 MI FROM THE XING RESTR (HARVEY VOR 115 DME) TO INITIATE AN IDLE PWR DSCNT. SHORTLY THEREAFTER, ZME INSTRUCTED US TO 'DSND TO FL310,' SAYING NOTHING FURTHER, WHICH WE INTERPRETED TO MEAN THAT HE IS CONCERNED THAT WE MIGHT NOT MAKE OUR XING RESTR 115 NM N OF HARVEY VOR AT FL280. THE CTLR AT THIS POINT IS VERY BUSY WITH OTHER RADIO CALLS AND WE ARE DSNDING AT 3000 FPM. WHILE APCHING FL290, HE REQUESTS OUR ALT AND WE RESPOND 'APCHING FL290,' TO WHICH HE REPLIES, 'MAINTAIN FL290' AND THAT WE WERE SUPPOSED TO HAVE MAINTAINED FL310. I TOLD HIM THAT WE MEETING OUR DSCNT REQUIREMENTS IN ORDER TO COMPLY WITH HIS PREVIOUS CLRNC FOR THE XING RESTR AND THAT HE HAD NEVER NEGATED THAT CLRNC BY INSTRUCTING US TO 'DELETE PREVIOUS RESTR TO CROSS 115 MI N OF HARVEY AT FL280' OR ANY WORDS OTHER THAN TO 'DSND TO FL310.' I TOLD CTR THAT WE NEVER RECEIVED NOR HAD WE ACKNOWLEDGED AN AMENDMENT OR CANCELLATION OF HIS XING RESTR CLRNC TO WHICH HE RESPONDED 'WELL SOMEBODY DID!' THIS IS THE SECOND TIME THIS YR I HAVE DSNDED TO AN ALT BASED UPON A XING RESTR BY CTR, ONLY TO HAVE CTR CHANGE (APPARENTLY) ITS MIND AND NOT CANCEL/NEGATE THE DSCNT CLRNC IN STANDARD, EASILY UNDERSTOOD RADIO PHRASEOLOGY. I QUERIED THE COPLT ON ALL ASPECTS OF THIS EVENT AND HIS INTERP OF ALL RADIO CALLS AND ACTIONS WERE THE SAME AS MINE. CTR CTLRS NOR WE CANNOT PERMIT TFC VOLUME/RADIO CALLS TO COME BEFORE CLR, CONCISE RADIO PHRASEOLOGY SO THAT THERE IS NO POSSIBLE MISINTERP AS TO WHAT THE OTHER MEANS OR EXPECTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS CALLED AND COUNSELED TO ASSURE HE HAD A PROPER UNDERSTANDING OF ARTCC PHRASEOLOGY AND HOW AN ALT ASSIGNED CHANGES ANY PREVIOUS CLRNCS. RPTR AND HIS FO WERE POSITIVE THE CTLR ALT ASSIGNMENT WAS AN ENCOURAGEMENT TO BEGIN DSCNT AND NOT A RESTR. AT LEAST HE WAS PROUD OF THE FACT THAT HE INQUIRED OF THE FO AND THEY WERE IN AGREEMENT OF WHAT THE NEW CLRNC MEANT TO THEM. RPTR WAS COUNSELED THAT ANY TIME A NEW ALT IS ISSUED TO HIM THAT IT WAS NOW A MANDATORY CLRNC TO SUPERSEDE ANY PREVIOUS CLRNC. RPTR EXPRESSED THANKS FOR BEING ENLIGHTENED AND WOULD SPREAD THE WORD TO OTHER FLC SO ALL MAY HAVE A PROPER UNDERSTANDING OF SUCH PROCS.

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.