THIS INVESTIGATION WAS OPENED AFTER NOTIFICATION FROM A NEW YORK CITY BUS FLEET OF A MARCH 25, 2004 INCIDENT WHERE A SEAT COLLASPED ON A TRANSIT BUS SENDING TWO PASSENGERS TO THE FLOOR, RESULTING IN ONE INJURY.AN INSPECTION REVEALED THAT THERE ARE TWO SEAT DESIGNS INSTALLED IN THE BUSES.SEAT DESIGN ?A? SUFFERED THE FAILURE WHERE THE PASSENGERS FELL TO THE FLOOR.AN EXAMINATION OF THIS SEAT DESIGN REVEALED THAT THE SEATS WERE NOT PROPERLY SECURED TO THE WALL MOUNTING BRACKETS AND THEREFORE LOST THEIR RIGIDITY AND STABLILTY ALLOWING THE COLLAPSE.THIS PROBLEM IS DEEMED TO BE MAINTENANCE RELATED.FLEET PERSONNEL FURTHER STATED THAT AFTER EXAMINING THE REMAINING BUSES IN THE FLEET, 259 SEAT BRACKETS ON 223 BUSES WERE DISCOVERED TO HAVE SOME QUANTITY OF FRAME CRACKS.THE CRACKED SEAT DESIGN IS DESIGNATED AS SEAT FRAME ?B.?THE MAJORITY OF THE CRACKED SEATS (?B?) ARE LOCATED JUST FORWARD OF THE EXIT DOOR ON THE CURB SIDE OF THE BUS.THESE BUSES ARE A RELATIVELY LOW POPULATION VEHICLE, HAVING BEEN BUILT ONLY IN 1998 AND 2002 MODEL YEARS.THE BUSES ARE DIFFERENT FROM MOST IN THAT THEY WERE SPECIFIED WITH ?HIGH FLOORS.? (SUMMARY CONTINUED ON PAGE 2)