CERTAIN GIRARDIN SCHOOL AND COMMERCIAL BUSES MANUFACTURED BETWEEN MARCH AND DECEMBER 2006. THE DEFECT INVOLVES THE INTERLOCK SWITCH SYSTEM IN THE LIFT NOT DETECTING THE PRESENCE OF A PASSENGER (EITHER WHEELCHAIR OR STANDEE) ON THE RICON WHEELCHAIR PLATFORM LIFT WHICH DOES NOT CONFORM TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 404, PLATFORM LIFT SYSTEMS FOR MOTOR VEHICLES. IN THE EVENT THIS CONDITION OCCURS DURING PASSENGER OPERATIONS IT MAY BE POSSIBLE FOR THE WHEELCHAIR TO TIP BACKWARDS ONTO THE PLATFORM WHEN THE PLATFORM WAS LOWERED.