ATC ISSUED CLIMB CLRNC TO THE WRONG ACFT.

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BTWN XA50 EST AND XB00 EST THREE OF OUR COMPANY FLTS DEPART NY METROPOLITAN ARPTS WITH SIMILAR CALL SIGNS. FLTS AXA; BXA AND BYA DEPART FROM EITHER NEWARK (EWR); (FLTS AXA AND BXA); OR LAGUARDIA (BYA); BOUND FOR ALBANY; NY (ALB); OR PROVIDENCE; RI (PVD); RESPECTIVELY. ALL 3 OF THE FLTS ARE ROUTED ON THE BRIDGEPORT VOR (BDR) 249 DEG RADIAL AND THENCE ON THEIR OWN INDIVIDUAL ROUTING. THE POOR NY APCH CTLR WAS WORKING ALL 3 OF OUR FLTS THAT EVENING; ON TOP OF MANY OTHERS. IN THE PROCESS OF ISSUING ALTS AND CLRNCS HE TRANSPOSED 2 FLTS; BXA TO PVD AND OUR; BYA TO ALB. 1ST HE CLRED BXA UP V-91 OUT OF BDR; MAINTAIN 9000'. THE CREW OF BXA STRAIGHTENED OUT THE MISTAKE; AND WERE CLRED TO 12000' ON THEIR FLT PLANNED ROUTE. THEN HE ISSUED US (BYA) A CLRNC TO CLB TO 12000'; DIRECT SOARS INTXN. AFTER READING BACK THE CLRNC I BEGAN AN ASCENT TO 12000' AND UP TO SOARS. FORTUNATELY; HE CAUGHT HIS ERROR BEFORE WE GOT PAST 9300' AND WE DSNDED BACK TO 9000' BEFORE ANY CONFLICT OCCURRED. I FLY THIS TRIP (BYA) AT LEAST TWICE A WK AND AM COGNIZANT OF THE CLOSE SIMILARITIES BTWN THE FLT #S; AND USE CAUTION ON THE CLRNCS. THE CTLR SAID BYA WHEN HE SHOULD HAVE SAID BXA; AND VICE VERSA. LUCKILY NO DAMAGE WAS DONE AND COOLER HEADS PREVAILED. BUT THIS IS A LETHAL POWDER KEG WAITING TO BLOW. I MENTIONED TO OUR SCHEDULE MAKER AND CHIEF PLT ABOUT THIS POOR SITUATION. I JUST HOPE THIS IS CHANGED BEFORE ANY PROBS OCCUR. MY SUGGESTION IS CHANGE THE FLT #S TO SOMETHING LESS SIMILAR SOUNDING. IF THAT CANNOT BE DONE; USE EXTREME CAUTION; CONFIRM AND READ BACK FULL FLT #S AND CALL SIGNS AND MOST IMPORTANT; USE STANDARD TERMINOLOGY ONLY.