A DHC-8-400 WITH A PILOT REPORT OF NOSE STEERING TROUBLE. SUPERVISOR INSTRUCTS TECHNICIANS TO MOVE AIRCRAFT WITH ENGINE POWER. LOSS OF AIRCRAFT CONTROL INCURRED DAMAGE TO AIRCRAFT AND GROUND EQUIPMENT.

Narrative

RECEIVED NOTIFICATION FROM OUR MAINT CTLR THAT ACFT HAD A PLT REPORT OF PROBS WITH THE NOSEWHEEL STEERING SYSTEM. AT AROUND XA:20 I HEARD THE MECHS CALL FOR THE TOW TEAM TO PULL THE ACFT FORWARD ONTO GREASE PLATES FOR TROUBLESHOOTING. AT AROUND XA:15 I HEARD THE MECH CALL AGAIN ASKING FOR TOW TEAM SUPPORT. AT AROUND XA:20 I INSTRUCTED MY LEAD AND MECHS TO USE THE ACFT ENGS TO MOVE THE ACFT FORWARD ONTO THE GREASE PLATES SO THE TROUBLESHOOTING COULD CONTINUE. THE MECHS CLEARED THE IMMEDIATE AREA AROUND THE ACFT OF OBSTRUCTIONS AND BEGAN A PRE-START WALKAROUND OF THE ACFT. AT THE TIME THE ACFT WAS APPROX 2 FT SHORT OF THE NORMAL PARKING STOP LINE AND NEED TO BE REPOSITIONED APPROX 12 INCHES FORWARD SO THERE WAS SUFFICIENT CLRNC FOR MOVEMENT. MECH 1 WENT INTO THE FLT DECK AND STARTED THE PRE-START CHKLIST; MECH 2 WENT TO THE NOSE TO ACT AS AN OBSERVER; AND MECH 3 WAS INSIDE OR NEAR A MAINT VAN PARKED APPROX 30 FT FORWARD OF THE #1 ENG. I NOTICED THE #2 ENG COME TO THE START AND FEATHER CONDITION AND THEN TO WHAT APPEARED TO BE THE FLT IDLE MIN POSITION. THE ACFT STARTED TO MOVE VERY SLOWLY AND AT ABOUT 12 INCHES I NOTICED THE OBSERVER SIGNAL THE MECH IN THE PLT SEAT TO STOP. THE ACFT DID STOP AFTER ABOUT ANOTHER 12 INCHES BUT SLIPPED TO THE RIGHT ABOUT 2 FT WHILE ON THE GREASE PADS. THE ACFT THEN BRIEFLY STOPPED BUT STARTED TO ROLL BACKWARDS FOR ABOUT 5 FT; STOPPED AGAIN; AND THEN STARTED MOVING VERY SLOWLY FORWARD. ABOUT 15 FT AFTER THE ACFT STARTED MOVING FORWARD IT APPEARED THAT THE MECH IN THE PLT SEAT SHUT DOWN THE #2 ENG. THE ACFT CONTINUED TO ROLL VERY SLOWLY WITH THE #2 PROP STILL TURNING. AT ABOUT 25 FT; THE #2 PROP STRUCK A MAINT STAND WHILE IT WAS STILL TURNING. ADDITIONALLY THE #1 PROP WAS STATIC BUT CONTACTED A MAINT VAN THAT HAD BEEN ABOUT 30 FT IN FRONT OF THE ACFT. OTHER DAMAGE INCLUDED DAMAGE TO THE GPU POWER RECEPTACLE CAUSED BY THE GND CORD BEING PULLED OUT DURING THE ACFT MOVEMENT. IT APPEARS THAT THE MECH RUNNING THE ENGS DID NOT FOLLOW ESTABLISHED PROCS AND COMPLETE THE ENG START CHKLIST BEFORE STARTING ENGS. HE RELEASED THE PARKING BRAKE BEFORE STARTING THE #1 ENG AND DID NOT HAVE THE #1 SPU ON. THIS CONDITION RESULTED IN NOT HAVING NORMAL BRAKE SYSTEM PRESSURE. THE MECH ALSO FAILED TO REACT TO THE SITUATION QUICKLY AND DID NOT RESET THE PARKING BRAKE UNTIL AFTER IMPACTING THE STAND AND MAINT VEHICLE.