A320 TAXI MECHS LOST ACFT CTL AND SLID INTO A B757 AT THE GATE.

Narrative

ON JAN/WED/02; I WAS ASSIGNED TO TAXI ACFT WITH ANOTHER TECHNICIAN. WE WERE TO TAXI AN A320 ACFT FROM GATE TO COMPANY HANGAR. MY PARTNER (THE OTHER TECHNICIAN) TOOK L SEAT WHILE I TOOK R. L SEAT'S RESPONSIBILITIES INCLUDE CTL OF ACFT MOVEMENT AND BACKUP ON RADIO. I AM MAINLY RESPONSIBLE FOR RADIOS AND KEEP EYES OUT FOR ANYTHING. WE PUSHED OUT FROM GATE AND STARTED ENGS. GOT CLRNC FROM RAMP TWR TO PROCEED S ON THE TXWY. AS WE WERE GETTING CLOSE TO OUR ENTRANCE I CALLED THE FAA GND TWR FOR CLRNC TO TAXI FROM THE ENTRANCE TO COMPANY HANGAR. AT THIS TIME I WAS PAYING VERY CLOSE TO THE RADIO DUE TO A LARGE AMOUNT OF CHATTER WAS GOING ON ON THE FAA FREQ. THE FAA TWR CALLED BACK MY CALL SIGN AND TOLD ME THE TAXI INSTRUCTIONS. I REPEAT THE INSTRUCTIONS BACK IDENTING NOW AS ACR XYZ. OUR ACFT STARTED SLIDING TO THE L. MY PARTNER TRIED TO REESTABLISH CTL TAPPING THE BRAKES EVEN MORE AND MOVING THE TILLER. HE SAID 'WE'RE SLIDING; NOSEWHEEL ISN'T TURNING THE ACFT.' WE IMPACTED A B757 IN THE GATE. OUR L WINGTIP HIT THE TAIL SECTION JUST AFT OF THE APU EXHAUST. DURING THE TURN THE ACFT STARTED SLIDING; CTL COULD NOT BE REESTABLISHED UNTIL AFTER THE IMPACT. WE STOPPED THE ACFT. I CALLED THE FAA GND TWR; TOLD THEM WE HAD IMPACTED ANOTHER ACFT AND WERE AT THE ENTRANCE. MY PARTNER SHUT DOWN ENGS AFTER HE WAS ABLE TO STOP THE ACFT. I MEANWHILE CALLED OUR RAMP TWR AND COMPANY HANGAR AND INFORMED THEM OF THE SIT. DURING OUR MOVE THE ACFT WAS KEPT AT IDLE AND BRAKES APPLIED APPLICABLY.