PLT OF A BE33 TAXIES ACFT WITHOUT CLRNC. 'THOUGHT' HE HEARD HIS CALL SIGN SEVERAL TIMES BUT WAS DISTRACTED BY A PAX IN THE R SEAT WHO WAS TALKING AND ARPT HAD LOTS OF TFC. PLT ASSOCIATED TAXI CLRNC FROM A SIMILAR SOUNDING BUT DIFFERENT FBO.

Narrative

PRIOR TO TAXI FROM THE XYZ FBO AT FT LAUDERDALE INTL ARPT; I HAD OBTAINED THE ATIS INFO AND MY IFR CLRNC FROM CLRNC DELIVERY. WHILE STILL PARKED SHORT OF THE NORTHERN E/W TXWY; I MADE SEVERAL UNSUCCESSFUL CALLS TO THE GND CTLR. UPON MAKING ONE LAST CALL ON THE VERY BUSY FREQ; I HEARD; 'DDEF; TAXI TO RWY 27L.' I BEGAN MY TAXI TOWARD RWY 27; BUT THEN REALIZED THAT IT WASN'T RWY 27L THAT I DESIRED; AS THEY WERE USING BOTH RWYS 27R/L FOR DEPS. I STOPPED ON THE NORTHERN TXWY AND MADE SEVERAL MORE CALLS TO THE GND CTLR TO CONFIRM THAT I HAD PERMISSION TO CONTINUE TO 'RWY 27R.' I BELIEVED I HEARD THE GND CTLR SAY; 'DDEF AFFIRMATIVE.' WHAT I NOW BELIEVE OCCURRED WAS THAT ANOTHER ACFT BEGAN HIS TAXI FROM ANOTHER FBO ON THE S SIDE OF THE ARPT; FROM ANOTHER FBO ALSO WITH THE WORD 'ZFBO' IN ITS NAME. THE CALL SIGN OF THAT ACFT WAS THE VERY SIMILAR; 'DDEP.' BECAUSE OF THE SIMILAR SOUNDING CALL SIGNS; THE TENDENCY FOR BOTH THE CTLR AND I TO USE CONTRACTIONS; THERE WAS A TOTAL MISUNDERSTANDING OF THE INSTRUCTIONS AND TO WHOM THEY WERE ISSUED. 'DDEF AND DDEP' SOUND TOO MUCH ALIKE WHEN THE ENG IS RUNNING. THE FREQ IS VERY BUSY AND A VERY CHATTY PAX IS TRYING TO ENGAGE ME IN CONVERSATION ON THE INTERCOM. YES; I WAS USING EXCELLENT QUALITY HEADSETS; BUT THIS MISCOM STILL OCCURRED TO A VERY SENIOR AND EXPERIENCED PLT. I REALLY WASN'T AWARE OF THE TOTAL MISUNDERSTANDING UNTIL I HAD REACHED THE HOLD SHORT POINT OF RWY 27R AND HAD SWITCHED TO THE TWR (LCL) CTLR FOR TKOF CLRNC WHEN I HAD TO WAIT FOR THAT INDIVIDUAL 'CLR' A KING AIR 'DDEP' FOR TKOF ON RWY 27L!! IT WAS AT THAT POINT THAT I HAD THAT SINKING FEELING THAT I HAD; MOST LIKELY; TAXIED OUT WITHOUT CLRNC. IN THIS INSTANCE; THERE WERE NO OTHER GND CONFLICTS WITH OTHER ACFT; JUST A CLR CASE OF; 'HEARING WHAT YOU EXPECT TO HEAR; NOT WHAT IS ACTUALLY SAID!' AND I THOUGHT IT COULDN'T HAPPEN TO ME!!