Narrative:

On feb/fri/95, I was the captain (PNF) on a beechjet 400 en route from M58 to rsw (ft myers, fl). Only the first officer and I were aboard the aircraft. At about XA30Z just before entering the airspace of ZMA, ZJX gave us a clearance to 'cross st. Petersburg (pie) at and maintain FL270.' shortly after we had begun our descent, we were handed off to ZMA. That controller then said, 'cross st. Petersburg at FL270, maintain FL240.' we descended out of FL270, on the way to FL240, a few mi ahead of pie, and the controller questioned us as to why we were not following our clearance. He then stated that we were to have remained at FL270 until pie, and then descend to FL240. We asked what he wanted us to do. When there was no reply, we asked, 'do you want us to climb back to FL270?' after a long pause, he said something to the effect, 'there is no problem at all, maintain FL240 and contact ZMA, frequency XXX.xx.' both the first officer and I had no question that the latter clearance meant that we had to be at or below FL270 (a reiteration of jacksonville's crossing restr), on our way to FL240, by the time we crossed pie. We did not question or discuss it, other than to follow our standard, air carrier x-developed altitude reminder procedure, simply because we were perfectly clear in our own minds about what the controller had intended for us to do. In 34 yrs of flying, with considerable experience as a far part 121 air carrier pilot, I have never had a clearance that, in retrospect, seemed more ambiguous than the latter one, above. The first officer likewise agreed with this assessment. If the controller had wanted us to cross pie at exactly FL270, he should have explicitly stated this, and not given the clearance to descend to FL240 at the same time. The first officer and I had periodic discussions about this incident throughout the remainder of the day, and we both agreed that we had done exactly as we had been cleared, as stated by the controller. We both felt that the controller should have been much more specific if he wished to convey a clearance that, as was apparent after the fact, was non-standard (based upon our accumulated flight experience). On feb/mon/95, I called the quality assurance desk at miami ARTCC, and discussed this incident with a supervisor. He said that no traffic conflict had occurred, and that no administrative action had been taken. From my description of the event, he agreed that the clearance we received could have been easily misinterpreted, and he volunteered to check the tape recordings of the radio exchanges to get a clear picture of exactly what had transpired. In a telephone discussion on feb/thur/95, said that he had listened to the tapes that morning, and confirmed the accuracy of the account stated above. He again stated that our interpretation of the clearance was quite reasonable, under the circumstances. 1 very ironic, and perhaps ominous, result of my taking the time to follow up with miami ARTCC on this problem: they said that because my first officer and I were filing ASRS reports, he would consider filing a pilot deviation report to avoid repercussions at the center (even though some 7 days had transpired, after an occurrence that everyone agreed had caused no traffic conflict). They were of the strong belief that the 'anonymity' of the report would not prevent a follow-up action at the center - with negative overtones - being taken as a direct result of the ASRS report. It would indeed be an unintended consequence of the whole ASRS system if the first officer and I were to be 'violated' as a direct result of our conscientiously following up on the occurrence, and then lose our immunity for a 5 yr period. Our 'deviation' - if in fact it could be called that - was anything but willful, and we are absolutely convinced that a large percentage of professional pilots would have done exactly the same thing as we did, given the exact sequence of events.

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Original NASA ASRS Text

Title: MISUNDERSTANDING OF DSCNT CLRNC CAUSES PLT DEV.

Narrative: ON FEB/FRI/95, I WAS THE CAPT (PNF) ON A BEECHJET 400 ENRTE FROM M58 TO RSW (FT MYERS, FL). ONLY THE FO AND I WERE ABOARD THE ACFT. AT ABOUT XA30Z JUST BEFORE ENTERING THE AIRSPACE OF ZMA, ZJX GAVE US A CLRNC TO 'CROSS ST. PETERSBURG (PIE) AT AND MAINTAIN FL270.' SHORTLY AFTER WE HAD BEGUN OUR DSCNT, WE WERE HANDED OFF TO ZMA. THAT CTLR THEN SAID, 'CROSS ST. PETERSBURG AT FL270, MAINTAIN FL240.' WE DSNDED OUT OF FL270, ON THE WAY TO FL240, A FEW MI AHEAD OF PIE, AND THE CTLR QUESTIONED US AS TO WHY WE WERE NOT FOLLOWING OUR CLRNC. HE THEN STATED THAT WE WERE TO HAVE REMAINED AT FL270 UNTIL PIE, AND THEN DSND TO FL240. WE ASKED WHAT HE WANTED US TO DO. WHEN THERE WAS NO REPLY, WE ASKED, 'DO YOU WANT US TO CLB BACK TO FL270?' AFTER A LONG PAUSE, HE SAID SOMETHING TO THE EFFECT, 'THERE IS NO PROB AT ALL, MAINTAIN FL240 AND CONTACT ZMA, FREQ XXX.XX.' BOTH THE FO AND I HAD NO QUESTION THAT THE LATTER CLRNC MEANT THAT WE HAD TO BE AT OR BELOW FL270 (A REITERATION OF JACKSONVILLE'S XING RESTR), ON OUR WAY TO FL240, BY THE TIME WE CROSSED PIE. WE DID NOT QUESTION OR DISCUSS IT, OTHER THAN TO FOLLOW OUR STANDARD, ACR X-DEVELOPED ALT REMINDER PROC, SIMPLY BECAUSE WE WERE PERFECTLY CLR IN OUR OWN MINDS ABOUT WHAT THE CTLR HAD INTENDED FOR US TO DO. IN 34 YRS OF FLYING, WITH CONSIDERABLE EXPERIENCE AS A FAR PART 121 ACR PLT, I HAVE NEVER HAD A CLRNC THAT, IN RETROSPECT, SEEMED MORE AMBIGUOUS THAN THE LATTER ONE, ABOVE. THE FO LIKEWISE AGREED WITH THIS ASSESSMENT. IF THE CTLR HAD WANTED US TO CROSS PIE AT EXACTLY FL270, HE SHOULD HAVE EXPLICITLY STATED THIS, AND NOT GIVEN THE CLRNC TO DSND TO FL240 AT THE SAME TIME. THE FO AND I HAD PERIODIC DISCUSSIONS ABOUT THIS INCIDENT THROUGHOUT THE REMAINDER OF THE DAY, AND WE BOTH AGREED THAT WE HAD DONE EXACTLY AS WE HAD BEEN CLRED, AS STATED BY THE CTLR. WE BOTH FELT THAT THE CTLR SHOULD HAVE BEEN MUCH MORE SPECIFIC IF HE WISHED TO CONVEY A CLRNC THAT, AS WAS APPARENT AFTER THE FACT, WAS NON-STANDARD (BASED UPON OUR ACCUMULATED FLT EXPERIENCE). ON FEB/MON/95, I CALLED THE QUALITY ASSURANCE DESK AT MIAMI ARTCC, AND DISCUSSED THIS INCIDENT WITH A SUPVR. HE SAID THAT NO TFC CONFLICT HAD OCCURRED, AND THAT NO ADMINISTRATIVE ACTION HAD BEEN TAKEN. FROM MY DESCRIPTION OF THE EVENT, HE AGREED THAT THE CLRNC WE RECEIVED COULD HAVE BEEN EASILY MISINTERPRETED, AND HE VOLUNTEERED TO CHK THE TAPE RECORDINGS OF THE RADIO EXCHANGES TO GET A CLR PICTURE OF EXACTLY WHAT HAD TRANSPIRED. IN A TELEPHONE DISCUSSION ON FEB/THUR/95, SAID THAT HE HAD LISTENED TO THE TAPES THAT MORNING, AND CONFIRMED THE ACCURACY OF THE ACCOUNT STATED ABOVE. HE AGAIN STATED THAT OUR INTERP OF THE CLRNC WAS QUITE REASONABLE, UNDER THE CIRCUMSTANCES. 1 VERY IRONIC, AND PERHAPS OMINOUS, RESULT OF MY TAKING THE TIME TO FOLLOW UP WITH MIAMI ARTCC ON THIS PROB: THEY SAID THAT BECAUSE MY FO AND I WERE FILING ASRS RPTS, HE WOULD CONSIDER FILING A PLT DEV RPT TO AVOID REPERCUSSIONS AT THE CTR (EVEN THOUGH SOME 7 DAYS HAD TRANSPIRED, AFTER AN OCCURRENCE THAT EVERYONE AGREED HAD CAUSED NO TFC CONFLICT). THEY WERE OF THE STRONG BELIEF THAT THE 'ANONYMITY' OF THE RPT WOULD NOT PREVENT A FOLLOW-UP ACTION AT THE CTR - WITH NEGATIVE OVERTONES - BEING TAKEN AS A DIRECT RESULT OF THE ASRS RPT. IT WOULD INDEED BE AN UNINTENDED CONSEQUENCE OF THE WHOLE ASRS SYS IF THE FO AND I WERE TO BE 'VIOLATED' AS A DIRECT RESULT OF OUR CONSCIENTIOUSLY FOLLOWING UP ON THE OCCURRENCE, AND THEN LOSE OUR IMMUNITY FOR A 5 YR PERIOD. OUR 'DEV' - IF IN FACT IT COULD BE CALLED THAT - WAS ANYTHING BUT WILLFUL, AND WE ARE ABSOLUTELY CONVINCED THAT A LARGE PERCENTAGE OF PROFESSIONAL PLTS WOULD HAVE DONE EXACTLY THE SAME THING AS WE DID, GIVEN THE EXACT SEQUENCE OF EVENTS.

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.