Narrative:

Aircraft X took a climb clearance intended for aircraft Z. X, who was at FL180, climbed through the altitude of cpr Y, who was at FL190. Before I could catch and correct the incorrect readback, X had lost separation with Y. I continued the climb of X to reestablish separation. I attempted to recorrect the readback. Loss of separation was approximately 3.5 mi horizontally. This has been classified an operational error by my facility. As a contributing factor, all aircraft on frequency were being climbed to FL200. X was stopped at FL180 and traffic had been issued to X that Y (muz) was his traffic. Later X reported Y in sight. Traffic had been called to Y that an MD80 would be overtaking him and he would see the MD80 come underneath his right lower side. The muz reported the MD80 in sight. The next clearance was for air carrier Z departing from rdu, nc, to climb to FL200. X took the readback. X and Z could be considered similar call signs. X heard the muz call him in sight, assumed the next clearance would be for him (similar call signs) and that visual separation was being applied, 'chomping at the bit' to climb higher -- X assumed this was his clearance. Unfortunately, the clearance I gave Z that X took was an 'expeditious' clearance. X went from FL180 to FL186 in 1 hit of the radar. The next hit by the radar was greater than 5 mi away. (A legal hit). X was about 150 KTS faster and in front of Y when he climbed through his altitude.

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Original NASA ASRS Text

Title: ACFT X UNAUTH CLB THROUGH OCCUPIED ALT HAD LTSS FROM CPR Y. SYS ERROR PLTDEV.

Narrative: ACFT X TOOK A CLB CLRNC INTENDED FOR ACFT Z. X, WHO WAS AT FL180, CLBED THROUGH THE ALT OF CPR Y, WHO WAS AT FL190. BEFORE I COULD CATCH AND CORRECT THE INCORRECT READBACK, X HAD LOST SEPARATION WITH Y. I CONTINUED THE CLB OF X TO REESTABLISH SEPARATION. I ATTEMPTED TO RECORRECT THE READBACK. LOSS OF SEPARATION WAS APPROX 3.5 MI HORIZLY. THIS HAS BEEN CLASSIFIED AN OPERROR BY MY FACILITY. AS A CONTRIBUTING FACTOR, ALL ACFT ON FREQ WERE BEING CLBED TO FL200. X WAS STOPPED AT FL180 AND TFC HAD BEEN ISSUED TO X THAT Y (MUZ) WAS HIS TFC. LATER X RPTED Y IN SIGHT. TFC HAD BEEN CALLED TO Y THAT AN MD80 WOULD BE OVERTAKING HIM AND HE WOULD SEE THE MD80 COME UNDERNEATH HIS R LOWER SIDE. THE MUZ RPTED THE MD80 IN SIGHT. THE NEXT CLRNC WAS FOR ACR Z DEPARTING FROM RDU, NC, TO CLB TO FL200. X TOOK THE READBACK. X AND Z COULD BE CONSIDERED SIMILAR CALL SIGNS. X HEARD THE MUZ CALL HIM IN SIGHT, ASSUMED THE NEXT CLRNC WOULD BE FOR HIM (SIMILAR CALL SIGNS) AND THAT VISUAL SEPARATION WAS BEING APPLIED, 'CHOMPING AT THE BIT' TO CLB HIGHER -- X ASSUMED THIS WAS HIS CLRNC. UNFORTUNATELY, THE CLRNC I GAVE Z THAT X TOOK WAS AN 'EXPEDITIOUS' CLRNC. X WENT FROM FL180 TO FL186 IN 1 HIT OF THE RADAR. THE NEXT HIT BY THE RADAR WAS GREATER THAN 5 MI AWAY. (A LEGAL HIT). X WAS ABOUT 150 KTS FASTER AND IN FRONT OF Y WHEN HE CLBED THROUGH HIS ALT.

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.