Sfo controller described confused similar same company call sign event when the wrong strip was util...

Narrative:

Air carrier XXX was #1 for departure off runway 1R; the strip I was provided was air carrier xyy. The air carrier xyy departure strip was at ground control. During a extremely busy time; I taxied air carrier xyy into position and hold. Once traffic permitted; I cleared air carrier xyy to depart runway 1R; and at about 1/2 mile upwind; I advised air carrier xyy to contact nct departure. After switching to nct; the aircraft tagged up as air carrier XXX and nct called to ask us to scan air carrier XXX again. The radar coordinator did some coordination with nct and we discovered that the aircraft I called air carrier xyy on every transmission was actually air carrier XXX. I have not listened to any recordings; but if air carrier XXX used his correct call sign I did not catch the incorrect identification. In addition air carrier XXX took every one of my clearances for air carrier xyy. Note: no loss of separation occurred as air carrier xyy and air carrier XXX were fortunately on identical departure procedures. Pay closer attention to aircraft callsign during readbacks.

Original NASA ASRS Text

Title: SFO Controller described confused similar same company call sign event when the wrong strip was utilized and the wrong callsign used and read backs missed during all tower operations.

Narrative: Air Carrier XXX was #1 for departure off Runway 1R; the strip I was provided was Air Carrier XYY. The Air Carrier XYY departure strip was at Ground Control. During a extremely busy time; I taxied Air Carrier XYY into position and hold. Once traffic permitted; I cleared Air Carrier XYY to depart Runway 1R; and at about 1/2 mile upwind; I advised Air Carrier XYY to contact NCT Departure. After switching to NCT; the aircraft tagged up as Air Carrier XXX and NCT called to ask us to scan Air Carrier XXX again. The RADAR Coordinator did some coordination with NCT and we discovered that the aircraft I called Air Carrier XYY on every transmission was actually Air Carrier XXX. I have not listened to any recordings; but if Air Carrier XXX used his correct call sign I did not catch the incorrect identification. In addition Air Carrier XXX took every one of my clearances for Air Carrier XYY. Note: no loss of separation occurred as Air Carrier XYY and Air Carrier XXX were fortunately on identical departure procedures. Pay closer attention to aircraft callsign during readbacks.

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.

Attributes
ACN	888305
Time
Date	201005
Local Time Of Day	1801-2400
Place
Locale Reference	SFO.Airport
State Reference	CA
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance

Sfo controller described confused similar same company call sign event when the wrong strip was utilized and the wrong callsign used and read backs missed during all tower operations.