Narrative:

We were level at FL340 when we were queried by ATC regarding our ability to reach FL380 if we were given that clearance in 3 or 4 minutes. I asked the center if he meant whether we could reach FL380 in 4 minutes or if it was 4 minutes from now we would start a climb to FL380. He responded that the clearance would be in 3 or 4 minutes. I responded that we would have no problem reaching FL380. At some point shortly thereafter he responded to maintain FL360. We climbed to FL360 and after leveling there for approximately two minutes ATC queried us on our altitude. We responded that we were at FL360 per his instructions. He then informed us that there was an 'air carrier xyz' on the frequency and that the FL380 discussion and clearance to FL360 was for air carrier xyz. Only after that did air carrier xyz answer the radio call; and it was a significantly different conversation than we had been having because he had an accent of course and very broken english. I found it very difficult to understand air carrier xyz the one time that he responded after this event was essentially over. We continued to maintain FL360 per the controllers instructions at that point and no traffic conflict was noted. I was surprised by this mistake because I felt that we had solid communication with the controller and I had no knowledge of air carrier xyz until the event had already taken place. I felt that the controller dropped the ball on this one because of all the indicators that he was probably communicating with the wrong aircraft. All of my calls utilized 'abc xyz' in the radio calls. Since FL360 was our filed altitude that trap was easy to fall into when we were cleared to climb to FL360; even though it was apparently meant for air carrier xyz. The only thing that I could have added to the communication was when we climbed from FL340 to FL360 I should have specifically stated 'abc xyz out of FL340 for FL360' I am not sure that I specifically said that.

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Original NASA ASRS Text

Title: An HS125-800 crew acknowledged an altitude assignment that was meant for an air carrier aircraft with a similar sounding call sign and then climbed to that altitude undetected by ARTCC.

Narrative: We were level at FL340 when we were queried by ATC regarding our ability to reach FL380 if we were given that clearance in 3 or 4 minutes. I asked the center if he meant whether we could reach FL380 in 4 minutes or if it was 4 minutes from now we would start a climb to FL380. He responded that the clearance would be in 3 or 4 minutes. I responded that we would have no problem reaching FL380. At some point shortly thereafter he responded to maintain FL360. We climbed to FL360 and after leveling there for approximately two minutes ATC queried us on our altitude. We responded that we were at FL360 per his instructions. He then informed us that there was an 'Air Carrier XYZ' on the frequency and that the FL380 discussion and clearance to FL360 was for Air Carrier XYZ. Only after that did Air Carrier XYZ answer the radio call; and it was a significantly different conversation than we had been having because he had an accent of course and very broken English. I found it very difficult to understand Air Carrier XYZ the one time that he responded after this event was essentially over. We continued to maintain FL360 per the controllers instructions at that point and no traffic conflict was noted. I was surprised by this mistake because I felt that we had solid communication with the controller and I had no knowledge of Air Carrier XYZ until the event had already taken place. I felt that the Controller dropped the ball on this one because of all the indicators that he was probably communicating with the wrong aircraft. All of my calls utilized 'ABC XYZ' in the radio calls. Since FL360 was our filed altitude that trap was easy to fall into when we were cleared to climb to FL360; even though it was apparently meant for Air Carrier XYZ. The only thing that I could have added to the communication was when we climbed from FL340 to FL360 I should have specifically stated 'ABC XYZ out of FL340 for FL360' I am not sure that I specifically said that.

Data retrieved from NASA's ASRS site as of April 2012 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.