AN ACR RECEIVED A CLRNC TO AN ALT THAT WOULD HAVE RESULTED IN A CONFLICT. (THE CTLR CONFUSED COMPANY'S SIMILAR SOUNDING CALL SIGNS).

Narrative

DURING CRUISE SEGMENT FROM MEM TO JFK; WE WERE LEVEL AT FL330; AND BEGAN TO PICK UP LIGHT TURB FROM CLOUD TOPS. WE REQUESTED AND RECEIVED CLRNC TO FL350. APCHING FL350 IT WAS APPARENT THAT FL350 WAS NOT MUCH DIFFERENT THAN FL330; AND WE REQUESTED FL370. THE CTLR SAID TO STANDBY; AND THEN CAME BACK WITH A CLRNC TO CLB AND MAINTAIN FL370. PASSING FL363; CTR CALLED AND ASKED WHAT OUR PRESENT ALT WAS; AND UPON HEARING OUR REPLY OF FL363; HE SAID THAT WE BELONGED AT FL350; AND GAVE US AN IMMEDIATE R TURN OF 30 DEGS; AND A DSCNT TO FL350. HE ISSUED A TURN OF 30 DEGS TO THE CONFLICTING TFC (I BELIEVE THAT IT WAS ANOTHER ACR). CTLR; LATER; THANKED US FOR OUR HELP; AFTER INITIALLY QUERYING US; AS TO WHY WE WERE CLBING. WE ASSURED HIM THAT WE HAD BEEN CLRED; AND READ BACK THE CLRNC TO FL370. FACTORS CONTRIBUTING: RECENT CHANGES IN OUR COMPANY'S FLT NUMBERS PUT SIMILAR SOUNDING CALL SIGNS; IN USE. THE CTLR SAID; HE THOUGHT THAT IT MIGHT HAVE BEEN HIS FAULT; THAT HE WAS TIRED; AND THE ALL SIGNS WERE SIMILAR. HE THOUGHT THAT HE HAD CLRED OUR COMPANY FLT NUMBER XXHB; WE WERE FLT NUMBER XXAB; AND IT WAS ABOUT XA00 AM. SUPPLEMENTAL INFO FROM ACN 299672: CONTRIBUTING FACTORS: 1) OUR COMPANY USES LIKE CALL SIGNS ON SEVERAL FLTS AT THIS TIME; IE; COMPANY FLT NUMBERS XX92; XX62; XX07; XX67; 2) TIME OF DAY.