RAMP CREW FAILS TO REMOVE STEERING BYPASS PIN ON B737-700 PRIOR TO TAXI. LOSS OF CTL OCCURS WHEN NOSE GEAR CASTERS TO FULL L POSITION. RAMP PERSONNEL COMPOUND THE PROBLEM BY REMOVING THE PIN WITHOUT INFORMING THE FLT CREW; WHICH COULD HAVE RESULTED IN SERIOUS INJURY WHEN THE NOSE GEAR TURNED ABRUPTLY BACK TO NEUTRAL.

Narrative

AFTER A NORMAL WAVE OFF FROM THE RAMP BUT WITH NO BYPASS PIN SHOWN TO US; AFTER STARTING TAXI; ACFT HAD BEEN ROLLING APPROXIMATELY 50 FT STRAIGHT AHEAD. NOSEWHEEL TILLER SNAPPED ABRUPTLY FULL LEFT DEFLECTION. ACFT STARTED TO TURN OFF TXWY CTRLINE TOWARD THE GRASS. WE WERE GOING SLOW ENOUGH TO BRAKE ACFT TO A STOP. TURNED APPROX 20 DEGS OFF CTRLINE WITH ACFT SLIGHTLY L OF CTRLINE. TAXI LIGHT AND NOSEWHEEL TILLER SHOWED NOSEWHEEL AT FULL L DEFLECTION. WE HAD NO CONTROL OF THE NOSEWHEEL. MAINT WAS CALLED AND TOLD WE WANT A NOSE GEAR AND TIRE INSPECTION AS WE HAD BEEN MOVING/BRAKING ATTEMPTING TO STOP ACFT WITH NOSE GEAR AT FULL DEFLECTION; THUS PUTTING SIDE STRESS ON NOSE GEAR AND SCUFFING NOSE TIRES. WHILE WE WERE WAITING FOR A RETURN TO GATE ASSIGNMENT AND POSSIBLY TOW DUE TO POSITION OF NOSE GEAR; A RAMPER; UNKNOWN TO US DUE TO IT BEING SO DARK; HAD RUN BACK OUT TO THE ACFT AND THEN REMOVED THE HYDRAULIC BYPASS PIN; WITH NO COMMUNICATION WITH US. AS HE DID THAT THE NOSE GEAR SNAPPED BACK ABRUPTLY CENTERED. HE COULD HAVE BEEN INJURED BY DOING THAT WITHOUT OUR KNOWLEDGE. HE THEN HELD UP THE PIN FOR US TO SEE. WE THEN TAXIED BACK INTO THE GATE FOR THE MAINT INSPECTION; WHICH WAS SIGNED OFF BY MAINT WITH NO APPARENT DAMAGE. OUR CONTRACT RAMP COMPANY NEEDS TO HIRE BETTER RAMP EMPLOYEES; HAVE BETTER TRAINING AND SUPERVISION. RAMPERS SHOULD BE REQUIRED TO SHOW US THE BYPASS PIN AT ALL STATIONS. CAPTS SHOULD TEST NOSE GEAR STEERING IMMEDIATELY UPON TAXI INITIATION.