Narrative:

This report is in response to a possible pilot deviation that occurred in feb/09. The conflict resulted from confusion over 2 similar call signs. I was the captain and pilot flying of air carrier X flight ab; when center cleared what was believed to be air carrier X flight ab to descend to FL230 and then discretion FL210. We were later told the clearance was meant for an air carrier Y flight cabin attendant. After several stepdowns; we were given the above descent clearance; which seemed appropriate at the time since we were close to our top-of-descent point. The first officer read it back and I started down and was probably 300-400 ft below our initial altitude when center told us to level off at FL320. We still had no idea a problem had occurred at this point. It wasn't until I asked for speed relief (we had been held high) from a crossing restriction that I was told to contact another frequency. This particular controller provided me with a quick explanation of what had happened and given a number to contact. We were then told to contact approach. At the gate; I called and spoke with the center supervisor about the situation. He explained that he had listened to the tapes and that we had apparently taken the clearance intended for the air carrier Y flight. I explained that the first officer had read back the clearance and was never corrected by the controller; nor was the transmission blocked in any way. Furthermore; there was never any indication the clearance was not intended for us. Our conversation ended with the supervisor telling me both sides were partially responsible for the misunderstanding.

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Original NASA ASRS Text

Title: An air carrier crew began a descent from a cruise altitude after hearing and acknowledging a descent clearance for an aircraft with a similar call sign. No controller similar call sign caution was issued.

Narrative: This report is in response to a possible pilot deviation that occurred in Feb/09. The conflict resulted from confusion over 2 similar call signs. I was the Captain and pilot flying of Air Carrier X Flight AB; when Center cleared what was believed to be Air Carrier X Flight AB to descend to FL230 and then discretion FL210. We were later told the clearance was meant for an Air Carrier Y Flight CAB. After several stepdowns; we were given the above descent clearance; which seemed appropriate at the time since we were close to our top-of-descent point. The First Officer read it back and I started down and was probably 300-400 FT below our initial altitude when Center told us to level off at FL320. We still had no idea a problem had occurred at this point. It wasn't until I asked for speed relief (we had been held high) from a crossing restriction that I was told to contact another frequency. This particular Controller provided me with a quick explanation of what had happened and given a number to contact. We were then told to contact approach. At the gate; I called and spoke with the Center Supervisor about the situation. He explained that he had listened to the tapes and that we had apparently taken the clearance intended for the Air Carrier Y flight. I explained that the First Officer had read back the clearance and was never corrected by the Controller; nor was the transmission blocked in any way. Furthermore; there was never any indication the clearance was not intended for us. Our conversation ended with the Supervisor telling me both sides were partially responsible for the misunderstanding.

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.