ACFT EQUIP PROB. ENG START DISRUPTED ELECTRICAL CIRCUIT CAUSING BRAKE FAILURE. RWY INCURSION.

Narrative

WHILE TAXIING FOR DEP ON THE #2 ENG ONLY; WE RECEIVED THE TAXI CLRNC 'TAXI VIA TXWY C AND TXWY K; HOLD SHORT RWY 5.' AS WE TAXIED EBOUND ON TXWY C WE COMPLETED THE TAXI CHKLIST. SUBSEQUENTLY; A SABRELINER APPEARED AHEAD OF US TAXIING FROM OUR L TO R ON TXWY B. WE THEN RECEIVED THE CLRNC 'FOLLOW THE SABRELINER; CROSS RWY 5; TAXI TO RWY 34;' AND WE WATCHED THE SABRELINER TAXI VIA TXWY B; RWY 16; RWY 23; AND TURN L ON TXWY K. OUR TAXI CHKLIST COMPLETE; THE COPLT STARTED THE #1 ENG AS WE APCHED THE INTXN OF TXWY C AND TXWY K. THE ACTION OF STARTING THE ENG FAULTED THE AC WILD #2 GENERATOR; CAUSING FAILURE OF THE HYD SYS SUPPLYING THE NORMAL BRAKES. THIS OCCURRED JUST PRIOR TO MY APPLYING THE BRAKES FOR THE 60 DEG R TURN TO TXWY K. AFTER REALIZING THAT THE NORMAL BRAKES WERE INEFFECTIVE; I APPLIED THE EMER BRAKES BUT OUR MOMENTUM CARRIED US ONTO RWY 34 WHICH WAS THE ACTIVE RWY. THE GND CTLR SIMPLY SAID 'OH YOU MISSED IT; TURN R ON RWY 23 AND L ON TXWY K;' WHICH WE DID. THE START SEQUENCE HAVING BEEN COMPLETED; THE AC WILD SYS WAS AUTOMATICALLY RESET RESTORING THE NORMAL BRAKES. WE TAXIED WITHOUT FURTHER INCIDENT. I ATTRIBUTE THE CAUSE TO A SERIES OF DECISIONS AND OCCURRENCES; THE REMOVAL OF ANY ONE OF WHICH WOULD HAVE PREVENTED THE INCIDENT. HAD WE STARTED THE ENG AT ANY OTHER TIME THAN THE CRITICAL TIME THAT WE CHOSE; HAD THE AC WILD #2 NOT DROPPED OFF-LINE WHICH NEITHER OF US HAD OBSERVED BEFORE; HAD WE BEEN AT A LIGHTER WT; THEN IT WOULD NOT HAVE BEEN A PROB. CORRECTIVE ACTION FOR THIS WOULD BE TO ANTICIPATE THE LOSS OF NORMAL BRAKING AT ANY TIME DURING TAXI; AND PARTICULARLY DURING ENG START. THE TAXI SHOULD BE PLANNED ACCORDINGLY WITH CAUTION EXERCISED IN THE VICINITY OF ACTIVE RWYS AS AT PROVIDENCE; RI; WHERE THE TXWY C TO TXWY K INTXN IS A VERY SHORT DISTANCE FROM THE RWY 16/34.