WHILE TAXIING FROM THE HANGAR TO THE TERMINAL WITH ONLY #2 ENGINE AND APU RUNNING ON AN AIRBUS A320; MECHANIC REPORTS HE LOST NOSE WHEEL STEERING JUST WHEN HE WAS CLEARED TO CROSS THE ACTIVE RUNWAY. BRAKE STEERING CONTROL UNIT (BSCU) IS SUSPECTED.

Narrative

I WAS TAXIING AN AIRPLANE FROM THE HANGAR TO THE TERMINAL AND I WAS TAXIING ON 1 ENG DUE TO THE FACT THAT THE FUEL ON THE L SIDE WAS BELOW MINIMUM TO TAXI WITH. I LOST NOSEWHEEL STEERING WHEN I WAS CLRED TO CROSS THE ACTIVE RWY. I HAD THE APU RUNNING AND THE ELECTRIC HYD PUMPS ON. NOTIFIED GND CTL THAT I LOST NOSEWHEEL STEERING; THAT I WAS STOPPING TO CORRECT THE PROB. I RETURNED TO THE HANGAR AND INSPECTED THE NOSE GEAR AND STEERING SYS; NOSE DISCREPANCIES NOTED. I THEN TAXIED THE ACFT ON BOTH ENGS TO THE LINE WITHOUT INCIDENT. TAXIING ON 1 ENG INSTEAD OF USING BOTH ENGS TO TAXI ON; IN ORDER TO HAVE FULL NOSEWHEEL STEERING. TAKING TIME TO MAKE SURE THAT I FOLLOW THE GUIDELINES; WHEN TAXIING THE AIRBUS ACFT IN THE FUTURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED AFTER RETURNING TO HANGER; THE BRAKE STEERING CONTROL UNIT (BSCU) AND NOSE STEERING SEEMED TO FUNCTION PROPERLY. REPORTER STATED HE WAS INFORMED BY OTHER MECHANICS; THAT A SPECIFIC CIRCUIT BREAKER COULD BE PULLED THAT WOULD PREVENT THE LOSS OF NOSE WHEEL STEERING DURING A ONE-ENGINE TAXI OF THE AIRBUS A320. BUT HE COULDN'T REMEMBER AT THE MOMENT WHICH ONE.