Narrative:

I was giving training to a trainee on a high altitude radar sector. An intermediate sector below us gave a radar handoff on air carrier climbing to FL270. Air carrier checked on climbing to FL270, my trainee said roger, expect further climb clearance in 10 mi. Trainee then stated air carrier climb and maintain FL310 that will be the final. Air carrier X read back climbing to FL310. What happened: air carrier X took a clearance given to company air carrier. Air carrier X never requested FL310, but took this clearance not issued to him without even questioning it. After he had been level FL280 for 200 mi, company air carrier similar a/north who gave the clearance to, never came back and told us someone else took his clearance. Problems that need to be idented: too many similar sounding call signs by same company in same vicinity at the same time. Pilots need more cockpit discipline. Controllers are having to repeat clrncs 2-3 times before pilots get it right. Supplemental information from acn 225204: I was training at position at washington ARTCC when sector 60 handed off an air carrier, same company, similar a/north, as air carrier X climbing to FL270. I took the handoff and called sector 60 and told them to put air carrier on a 240 degree heading. Moments later, air carrier checks on frequency, level at FL270 on a 240 degree heading. I advise him I will have higher shortly. I pvd his data tag on R32 and manually point him out. I then climbed air carrier to FL310 and advise him that will be his final altitude for traffic. Next thing I know, air carrier Y, over montebello, says the traffic off his left wing is climbing. I quickly turn air carrier X (the traffic) to a 180 degree heading away from air carrier Y and air carrier Z and descend him to FL280. At the time the data block on air carrier X showed FL280 and FL283. The air carrier X climbed through FL290 before going back to FL280, this also caused a confliction with air carrier Z. Supplemental information from acn 224903: center called on 134.62 and said, 'air carrier X, climb and maintain FL310 that will be your final today.' I read back, 'air carrier X climb to 310 and that will be a final.' we set 31000 ft in the MCP and started a climb. At 29500 ft, center said, 'air carrier X, turn left to 180 and descend to 280.' center then said, 'company air carrier, climb to FL310 and that will be a final.' air carrier read back the clearance. I called center and said, 'center, was that climb clearance not for air carrier X?' he said, 'no, it was not.' before we left the frequency, I asked the controller 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 aircraft on frequency with a similar call sign and we had heard no calls to company air carrier. When the first call was made, the first officer was distracted by a flight attendant in the cockpit asking about the temperature of the cabin and he did not hear the call sign read by center. Supplemental information from acn 224896: our call sign same company air carrier similar to air carrier X, our requested cruise altitude was at FL280. We were flying at assigned altitude of FL270 and center call was made for air carrier to climb to FL310. Air carrier X answered and since we were not filed above FL280, we did not question if radar call was for us. A couple mins later, air carrier X was given a descent clearance and vector. We, air carrier, were given a climb to FL310.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.