BREAKDOWN IN COCKPIT DISCIPLINE AND SOP ABOARD A B733 RESULT IN NOT 1; BUT 2 BROKEN TOWBARS DURING PUSHBACK.

Narrative

WE HAD BEEN DEALING WITH SOME MINOR MAINT ISSUES ON OUR FIRST 2 LEGS AND WERE RUNNING ABOUT 10 MINS LATER. I HAD ASKED MY FO TO FLIP MY SWITCHES PRIOR TO OUR PUSHBACK WHILE I BRIEFED PAX AND FINISHED TALKING TO MAINT. WE RAN THE BEFORE START CHKLIST. I WAS STANDING BTWN THE SEATS. I DO THIS CHKLIST FROM THIS POS ABOUT 50% OF THE TIME. ABOUT 3 MINS LATER; I CLBED INTO MY SEAT AND STRAPPED IN. AS I WAS CONTACTING THE PUSHBACK CREW; MY FO TOLD ME WE WERE CLRED TO PUSH AND THE FLT ATTENDANT GAVE ME THE NAPKIN AND TOLD ME THE CABIN WAS SECURE. OUR PUSH COMMENCED STRAIGHT BACK. AFTER ABOUT 10 FT; WE HEARD AND FELT THE SHEAR PIN BREAK. WE SET THE BRAKE AND THE PUSHBACK CREW GOT ANOTHER TOWBAR. THIS WAS MY FIRST BROKEN TOWBAR. WE WERE HVY; SO IT REALLY DIDN'T ALARM ME. WE GOT HOOKED UP AGAIN AND STARTED TO PUSH AGAIN. AFTER ABOUT 10 MORE FT; WE FELT THE SHEAR PIN BREAK AGAIN. I SET THE BRAKES AND CALLED MAINT AS I SCANNED THE COCKPIT. JUST AS MAINT ANSWERED; I SAW THE A'S ON AND B'S OFF. I REPOSITIONED THE SWITCHES; BLED THE A; AND COMPLETED THE PUSHBACK/FLT UNEVENTFULLY. I PRIDE MYSELF ON CHKLIST PROCS AND CATCHING MISPLACED SWITCHES. THIS TIME; I LET DISTRS AND THE DESIRE TO GET BACK ON TIME DISTRACT ME FROM TWICE CONFIRMING THE SWITCHES WERE RIGHT. MY PLAN IS TO NOW STERILIZE MY CHKLIST AND INITIAL COM WITH THE PUSHBACK CREW. IT HAPPENED TO ME ONCE; NEVER AGAIN.