Narrative:

Occurrence was at night, during a very congested time period. Tower issued us an immediate takeoff clearance (we believe the clearance was meant for another aircraft but our call sign was used). We executed in immediate takeoff. At approximately 100 KTS the tower repeated our call sign and to continue takeoff. We continued, were issued a departure heading and later switched to departure frequency. The tower controller did not give us any indications of a fault occurring. The flight proceeded without incident. We were later informed by the crew of another aircraft of the mix-up. At phl with 2 active runways at a time it may be possible to send aircraft with a similar call sign (company name, etc) to the same runway. This would prevent confusion of different aircraft that would be in position for a particular runway.

Related reports:

Google
 

Original NASA ASRS Text

Title: COMMUTER LTT CLRNC RESPONSE TO WRONG CALL SIGN UNAUTHORIZED TKOF.

Narrative: OCCURRENCE WAS AT NIGHT, DURING A VERY CONGESTED TIME PERIOD. TWR ISSUED US AN IMMEDIATE TKOF CLRNC (WE BELIEVE THE CLRNC WAS MEANT FOR ANOTHER ACFT BUT OUR CALL SIGN WAS USED). WE EXECUTED IN IMMEDIATE TKOF. AT APPROX 100 KTS THE TWR REPEATED OUR CALL SIGN AND TO CONTINUE TKOF. WE CONTINUED, WERE ISSUED A DEP HDG AND LATER SWITCHED TO DEP FREQ. THE TWR CTLR DID NOT GIVE US ANY INDICATIONS OF A FAULT OCCURRING. THE FLT PROCEEDED WITHOUT INCIDENT. WE WERE LATER INFORMED BY THE CREW OF ANOTHER ACFT OF THE MIX-UP. AT PHL WITH 2 ACTIVE RWYS AT A TIME IT MAY BE POSSIBLE TO SEND ACFT WITH A SIMILAR CALL SIGN (COMPANY NAME, ETC) TO THE SAME RWY. THIS WOULD PREVENT CONFUSION OF DIFFERENT ACFT THAT WOULD BE IN POS FOR A PARTICULAR RWY.

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.