Narrative:

I received an IFR clearance and was cleared to taxi to runway 9R. I did the preflight then I called the tower and was told to hold after a few minutes; I heard the tower call 'aircraft X; cleared for takeoff heading 090 degrees; maintain 2;000 ft.' after takeoff; the tower called me and asked my intentions and that I was not cleared for takeoff and to call tower after landing. I did so and the supervisor told me that he did not hear my call back on the tape (maybe I was stepped on by the airline) and told me that there was a similar call sign flight taking off from runway 9L and maybe that was the mistake. It was a deviation; maybe I heard wrong because I was a cirrus and the other aircraft was an air carrier; but I am positive that I called back like I always do before taxiing in position for takeoff and taxi also; and there was no answer back so I figure that I was cleared for takeoff.

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Original NASA ASRS Text

Title: Private pilot reports call sign confusion with an airliner using similar sounding call sign and possible takeoff clearance acceptance not meant for the reporter.

Narrative: I received an IFR clearance and was cleared to taxi to Runway 9R. I did the preflight then I called the Tower and was told to hold After a few minutes; I heard the Tower call 'Aircraft X; cleared for takeoff heading 090 degrees; maintain 2;000 FT.' After takeoff; the Tower called me and asked my intentions and that I was not cleared for takeoff and to call Tower after landing. I did so and the Supervisor told me that he did not hear my call back on the tape (maybe I was stepped on by the airline) and told me that there was a similar call sign flight taking off from Runway 9L and maybe that was the mistake. It was a deviation; maybe I heard wrong because I was a Cirrus and the other aircraft was an air carrier; but I am positive that I called back like I always do before taxiing in position for takeoff and taxi also; and there was no answer back so I figure that I was cleared for takeoff.

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.