ACR X UNAUTHORIZED CLB THROUGH OCCUPIED ALT HAD LTSS FROM ACR Y AND Z. SIMILAR CALL SIGN SAME COMPANY. SYS ERROR. PLTDEV.

Narrative

I WAS GIVING TRAINING TO A TRAINEE ON A HIGH ALT RADAR SECTOR. AN INTERMEDIATE SECTOR BELOW US GAVE A RADAR HDOF ON ACR CLBING TO FL270. ACR CHKED ON CLBING TO FL270; MY TRAINEE SAID ROGER; EXPECT FURTHER CLB CLRNC IN 10 MI. TRAINEE THEN STATED ACR CLB AND MAINTAIN FL310 THAT WILL BE THE FINAL. ACR X READ BACK CLBING TO FL310. WHAT HAPPENED: ACR X TOOK A CLRNC GIVEN TO COMPANY ACR. ACR X NEVER REQUESTED FL310; BUT TOOK THIS CLRNC NOT ISSUED TO HIM WITHOUT EVEN QUESTIONING IT. AFTER HE HAD BEEN LEVEL FL280 FOR 200 MI; COMPANY ACR SIMILAR A/N WHO GAVE THE CLRNC TO; NEVER CAME BACK AND TOLD US SOMEONE ELSE TOOK HIS CLRNC. PROBLEMS THAT NEED TO BE IDENTED: TOO MANY SIMILAR SOUNDING CALL SIGNS BY SAME COMPANY IN SAME VICINITY AT THE SAME TIME. PLTS NEED MORE COCKPIT DISCIPLINE. CTLRS ARE HAVING TO REPEAT CLRNCS 2-3 TIMES BEFORE PLTS GET IT RIGHT. SUPPLEMENTAL INFO FROM ACN 225204: I WAS TRAINING AT POS AT WASHINGTON ARTCC WHEN SECTOR 60 HANDED OFF AN ACR; SAME COMPANY; SIMILAR A/N; AS ACR X CLBING TO FL270. I TOOK THE HDOF AND CALLED SECTOR 60 AND TOLD THEM TO PUT ACR ON A 240 DEG HDG. MOMENTS LATER; ACR CHKS ON FREQ; LEVEL AT FL270 ON A 240 DEG HDG. I ADVISE HIM I WILL HAVE HIGHER SHORTLY. I PVD HIS DATA TAG ON R32 AND MANUALLY POINT HIM OUT. I THEN CLBED ACR TO FL310 AND ADVISE HIM THAT WILL BE HIS FINAL ALT FOR TFC. NEXT THING I KNOW; ACR Y; OVER MONTEBELLO; SAYS THE TFC OFF HIS L WING IS CLBING. I QUICKLY TURN ACR X (THE TFC) TO A 180 DEG HDG AWAY FROM ACR Y AND ACR Z AND DSND HIM TO FL280. AT THE TIME THE DATA BLOCK ON ACR X SHOWED FL280 AND FL283. THE ACR X CLBED THROUGH FL290 BEFORE GOING BACK TO FL280; THIS ALSO CAUSED A CONFLICTION WITH ACR Z. SUPPLEMENTAL INFO FROM ACN 224903: CTR CALLED ON 134.62 AND SAID; 'ACR X; CLB AND MAINTAIN FL310 THAT WILL BE YOUR FINAL TODAY.' I READ BACK; 'ACR X CLB TO 310 AND THAT WILL BE A FINAL.' WE SET 31000 FT IN THE MCP AND STARTED A CLB. AT 29500 FT; CTR SAID; 'ACR X; TURN L TO 180 AND DSND TO 280.' CTR THEN SAID; 'COMPANY ACR; CLB TO FL310 AND THAT WILL BE A FINAL.' ACR READ BACK THE CLRNC. I CALLED CTR AND SAID; 'CTR; WAS THAT CLB CLRNC NOT FOR ACR X?' HE SAID; 'NO; IT WAS NOT.' BEFORE WE LEFT THE FREQ; I ASKED THE CTLR IF THIS HAD CAUSED A CONFLICT AND HE SAID; 'YES; IT DID.' I WOULD POINT OUT THE FOLLOWING: NO ONE HAD SAID THERE WAS AN ACFT ON FREQ WITH A SIMILAR CALL SIGN AND WE HAD HEARD NO CALLS TO COMPANY ACR. WHEN THE FIRST CALL WAS MADE; THE FO WAS DISTRACTED BY A FLT ATTENDANT IN THE COCKPIT ASKING ABOUT THE TEMP OF THE CABIN AND HE DID NOT HEAR THE CALL SIGN READ BY CTR. SUPPLEMENTAL INFO FROM ACN 224896: OUR CALL SIGN SAME COMPANY ACR SIMILAR TO ACR X; OUR REQUESTED CRUISE ALT WAS AT FL280. WE WERE FLYING AT ASSIGNED ALT OF FL270 AND CTR CALL WAS MADE FOR ACR TO CLB TO FL310. ACR X ANSWERED AND SINCE WE WERE NOT FILED ABOVE FL280; WE DID NOT QUESTION IF RADAR CALL WAS FOR US. A COUPLE MINS LATER; ACR X WAS GIVEN A DSCNT CLRNC AND VECTOR. WE; ACR; WERE GIVEN A CLB TO FL310.