FLC TAXIING ON TXWY WITH NOSEWHEEL ON CTRLINE COLLIDES R WINGTIP NAV LIGHT WITH PORTABLE AIR STAIR PARKED IN IMPROPERLY MARKED STORAGE AREA.

Narrative

AFTER LNDG AND WHILE TAXIING INBOUND INTO THE COMPANY RAMP AREA; THE R WINGTIP NAV LIGHT COVER BRUSHED AN ACFT ROLLUP STAIR UNIT WHICH WAS IMPROPERLY PARKED ADJACENT TO THE TXWY. THE ACFT UNDER MY CTL WAS TAXIED AT A SLOW PACE AND ON THE CTR DOUBLE YELLOW SAFETY LINE TO THE R OF THE TXWY. THIS AREA IS NORMALLY USED TO STORE EQUIPMENT AND IT IS CONSIDERED SAFE TO TRANSIT THIS AREA AS LONG AS THE ACFT IS ON CTRLINE AND THE EQUIPMENT IS BEHIND THE SAFETY LINE. NOTE: THIS IS THE NORMAL TAXI RTE WITHIN THE RAMP AREA. BOTH CONDITIONS WERE MET. THE FO WAS VISUALLY CHKING THE R SIDE; IT APPEARED VISUALLY THAT WE WOULD CLR THE STAIRS; THERE WAS NO ROOM TO MANEUVER TO THE L BECAUSE OF ACFT PARKED IN LINE ALONG THE TXWY. WE CONTINUED TO TAXI; THE R WINGTIP STRUCK THE STAIR UNIT. DAMAGE WAS CONFINED TO THE PLEXIGLASS COVER SURROUNDING THE R NAV LIGHT. UNDER DIRECTION OF SAFETY AND COMPANY PERSONNEL ANOTHER ACFT OF THE SAME SIZE AND TYPE WAS TAXIED UP TO THE STAIR UNIT AND IT WAS DETERMINED THAT THE WINGTIP LENGTH EXTENDED APPROX 3.5 FT BEYOND THE DOUBLE YELLOW SAFETY LINE AND IF THIS ACFT CONTINUED TO TAXI IT ALSO WOULD STRIKE THE STAIRS. PHOTOS AND MEASUREMENT WERE TAKEN AND THE STAIRS WERE MOVED. FOLLOWING A BOARD OF INVESTIGATION IT WAS DETERMINED THAT THE DOUBLE YELLOW LINE WAS NOT PROPERLY POSITIONED AND NEEDED TO BE REPAINTED. ALSO NO EQUIPMENT SHOULD BE PARKED IN THIS AREA WITH VERT HEIGHT IN EXCESS OF THE WING UNTIL THE REPAINTING IS ACCOMPLISHED.