B727 ACFT RECEIVING VECTORS AROUND WX WAS NOTIFIED BY COMPANY DISPATCH THAT ATC HAD COMPLAINED THAT THEIR SPD OF 280 KTS HAD BACKED UP TFC.

Narrative

WE DEPARTED RWY 26R AT ATL AT XA45 LCL. AT TKOF; THERE WERE TSTMS TO THE W; N; AND E OF THE ATL ARPT; AND THERE WERE WINDSHEAR ALERTS WITH PERIODIC MICROBURST WARNINGS. DURING DEP; WE REQUESTED VECTORS TO AVOID BUILD-UPS; COMING NO CLOSER THAN 5 NM. DEP CTL REQUIRED US TO LEVEL AT 10000 FT MSL; AND THEN SWITCHED US TO ZTL WHO AUTH A CLB TO 12000 FT MSL; WHERE WE WERE IN THE TOPS OF THE WX; AND STILL AVOIDING THE LARGER BUILD-UPS. WE WERE EXPERIENCING CONTINUOUS LIGHT CHOP AND HEARD OTHER ACFT ON FREQ RPTING LIGHT TO MODERATE TURB UP TO FL210. AS A RESULT OF THE TURB; AT 10000 FT WE ACCELERATED FROM 250 KIAS TO 280 KIAS (FLT MANUAL PUBLISHED TURB PENETRATION AIRSPD) AND MAINTAINED THIS SPD DURING OUR IMMEDIATE LEVELOFF. WE WERE NOT ALLOWED TO CLB ABOVE 12000 FT DUE TO JET TFC AHEAD OF US AT 14000 FT WHICH WAS BEING DISPLAYED ON TCASII. ALTHOUGH WE WERE INITIALLY CLRED DIRECT GQO; ZTL PROVIDED NUMEROUS VECTORS FROM 330 DEGS TO 020 DEGS BECAUSE OF TFC (WE ASSUMED THE 14000 FT TFC AHEAD). IN THE VICINITY OF GQO WE WERE GIVEN A CHANGE TO A SECOND ZTL FREQ. SHORTLY AFTER CHKING ON; THIS CTLR ASKED US IF WE HAD ADVISED THE PREVIOUS CTLR WE WERE SLOWING DOWN. HE WAS TOLD WE HAD NEVER SLOWED DOWN; BUT RATHER HAD MAINTAINED A SPD OF 280 KIAS FOR TURB. HE DID NOT REQUEST AN AIRSPD CHANGE. A SHORT TIME LATER WE RECEIVED A CALL FROM OUR FLT CTL DISPATCHER ASKING WHAT HAD HAPPENED; THAT HE HAD RECEIVED A COMPLAINT FROM ATC COMPLAINING WE HAD BACKED UP THE WHOLE SYS. OBSERVATIONS: 1) THE WX IN THE AREA WAS UNFORECAST AND BOTH DEP CTL AND CTR CTLRS APPEARED TO BE TASK SATURATED. 2) THE FIRST ZTL CTLR NEVER QUESTIONED OUR AIRSPD AND NEITHER CTLR ASKED US TO CHANGE AIRSPDS. 3) I BELIEVE ZTL MAY HAVE IDENTED THE WRONG ACFT. I FAIL TO SEE HOW WE COULD HAVE BACKED THE TFC UP WHEN WE WERE IN FACT BEING HELD DOWN AND VECTORED FOR TFC AHEAD OF US. RECOMMENDATIONS: IF A CTLR HAS SEPARATION PROBS; HE/SHE SHOULD COMMUNICATE WITH AFFECTED ACFT IN A TIMELY MANNER.