DURING PUSHBACK; WITH WING WALKERS; ACFT PUSHED INTO PARKED ACFT.

Narrative

THE L WINGTIP AREA AND L POS LIGHTS WERE DAMAGED ON THIS FLT DURING PUSHBACK. PER STANDARD PROC; I WAS IN INTERPHONE CONTACT WITH THE TUG DRIVER AND THE FO WAS MONITORING RAMP CTL. WE WERE CLRED BY RAMP CTL TO PUSH BACK FROM GATE XX; TAIL N. PUSHBACK WAS NORMAL UNTIL ESTABLISHED IN THE TURN TO TAIL N. WE WERE IN THE PROCESS OF STARTING THE #2 ENG WHEN THE ACFT AND TUG CAME TO AN ABRUPT; BUT NOT VIOLENT HALT WITH THE TOWBAR AT APPROX A 45 DEG ANGLE. I INITIALLY THOUGHT THERE WAS A PROB WITH THE TUG OR TOWBAR AND ASSUMED THE DRIVER WAS BUSY. A FLT ATTENDANT CALLED FROM THE AFT OF THE ACFT TO RPT THAT SHE THOUGHT WE HAD STRUCK ANOTHER ACFT. I INFORMED THE TUG DRIVER WHO VERIFIED THIS AND THE ACFT WAS TOWED BACK TO GATE. THE PARKING CHKLIST WAS COMPLETED AND THE VOICE RECORDER CIRCUIT BREAKER PULLED. NO CREW OR PAX WERE INJURED. I EVALUATED THE DAMAGE PERSONALLY AND AFTER CONSULTING WITH ACFT MAINT; THE ACFT WAS OTS. WE HAD NO INDICATION OF ANY PROB BEFORE CONTACTING THE OTHER ACFT FROM EITHER RAMP OR THE TUG DRIVER. WE WERE IN THE PROCESS OF STARTING THE ENGS AND WERE LOOKING AT THE ENG INSTS WHEN THIS OCCURRED.