Narrative:

Arriving tpa on the darbs 1 arrival with clearance to deviate as required. We were working our way through closely spaced cumulo nimbus. ZJX changed our arrival to the blond 2. At the time we were very busy. I had disengaged the autoplt to get more bank angle (30 degrees) and turn rate to maneuver through tightly spaced cells. The first officer was getting alternate WX (orl) as the WX was deteriorating at tpa. We had just passed between 2 cells on a southeast heading when ZJX requested we turn immediately back towards blond intersection. A turn in either direction would have put us into the cells we had just passed between. The controller then requested we squawk emergency and informed us we were conflicting with other arrs. No aircraft were visible on TCASII on the 20 NM scale and we were unaware of any aircraft affected by our deviation. ZJX turned us over to tpa approach for a normal recovery. It seems in recent yrs as the system has become more complex (more arrs available, more aircraft in system) that controllers often change clrncs in high workload sits without regard to the additional demands it places on the cockpit crews. They assume that because it is charted, that it is doable -- right now. That's not always the case, as is shown by the above incident.

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Original NASA ASRS Text

Title: ARTCC REQUESTS ACR TO SQUAWK EMER WHEN THEY ARE UNABLE TO FLY NEW CLRNC BECAUSE OF WX.

Narrative: ARRIVING TPA ON THE DARBS 1 ARR WITH CLRNC TO DEVIATE AS REQUIRED. WE WERE WORKING OUR WAY THROUGH CLOSELY SPACED CUMULO NIMBUS. ZJX CHANGED OUR ARR TO THE BLOND 2. AT THE TIME WE WERE VERY BUSY. I HAD DISENGAGED THE AUTOPLT TO GET MORE BANK ANGLE (30 DEGS) AND TURN RATE TO MANEUVER THROUGH TIGHTLY SPACED CELLS. THE FO WAS GETTING ALTERNATE WX (ORL) AS THE WX WAS DETERIORATING AT TPA. WE HAD JUST PASSED BTWN 2 CELLS ON A SE HDG WHEN ZJX REQUESTED WE TURN IMMEDIATELY BACK TOWARDS BLOND INTXN. A TURN IN EITHER DIRECTION WOULD HAVE PUT US INTO THE CELLS WE HAD JUST PASSED BTWN. THE CTLR THEN REQUESTED WE SQUAWK EMER AND INFORMED US WE WERE CONFLICTING WITH OTHER ARRS. NO ACFT WERE VISIBLE ON TCASII ON THE 20 NM SCALE AND WE WERE UNAWARE OF ANY ACFT AFFECTED BY OUR DEV. ZJX TURNED US OVER TO TPA APCH FOR A NORMAL RECOVERY. IT SEEMS IN RECENT YRS AS THE SYS HAS BECOME MORE COMPLEX (MORE ARRS AVAILABLE, MORE ACFT IN SYS) THAT CTLRS OFTEN CHANGE CLRNCS IN HIGH WORKLOAD SITS WITHOUT REGARD TO THE ADDITIONAL DEMANDS IT PLACES ON THE COCKPIT CREWS. THEY ASSUME THAT BECAUSE IT IS CHARTED, THAT IT IS DOABLE -- RIGHT NOW. THAT'S NOT ALWAYS THE CASE, AS IS SHOWN BY THE ABOVE INCIDENT.

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.