TAXIWAY EXCURSION BY TAXIING TFC IN A NIGHT OP.

Narrative

WHILE MAKING A 90 DEG TURN FROM THE RAMP ONTO TAXIWAY Y S; THE R MAIN WHEEL SLIPPED OFF THE PAVEMENT INTO THE ADJACENT SOFT DIRT. THE WHEEL AND BRAKE ASSEMBLY RECEIVED MINOR DAMAGE. PAX WERE DEPLANED WITHOUT INCIDENT; AND THE ACFT EXTRICATED USING AIR BAGS (BY ARPT CREWS). ACFT WAS BEING TAXIED BY THE CAPT AT THE TIME OF THE INCIDENT. CREW WAS PERFORMING TAXI CHKLIST; AND INITIAL THOUGHTS WERE THAT WE HAD A FLAT TIRE. VISUAL INSPECTION CONFIRMED ABOVE. CONTRIBUTING FACTORS WERE THE WIDTH; DESIGN; AND LIGHTING ON THE TAXIWAY: WIDTH: TAXIWAY WAS BUILT NARROWER THAN STANDARD; WITH PLANS TO WIDEN THEM LATER (AS PER ARPT MGR). DESIGN: TAXIWAY CORNER USES SEGMENTED INSTEAD OF SMOOTH CURVE. LIGHTING: BECAUSE OF PLANS TO WIDEN THE TAXIWAY; LIGHTING WAS INSTALLED FAR FROM THE PRESENT EDGE OF THE PAVEMENT; GIVING THE ILLUSION OF A WIDER SURFACE. THIS WAS; I BELIEVE; A PRIMARY FACTOR. THE YELLOW CTRLINE STRIPE; THOUGH PAINTED WITH REFLECTIVE PAINT; IS NEARLY INVISIBLE DUE TO THE LOW ANGLE OF ACFT TAXI LIGHTS AND THE HIGH COCKPIT VIEWING ANGLE. DURING WINTER MONTHS; THIS SITUATION WILL BE EVEN MORE HAZARDOUS.