IN MAY 2000, COT INITIATED A SERVICE BULLETIN INFORMING COLLINS BUS CORP.(COLLINS) OF AN ASSEMBLY PLANT ERROR ON BUS CHASSIS SUPPLIED TO THEM.CERTAIN CHASSIS BUILT FROM 9-1-99 TO 4-1-00 WERE NOT EQUIPPED WITH A QUICK RELEASE VALVE AND CONSEQUENTLY HAVE A SLOW PARKING BRAKE APPLICATION TIME.THE SERVICED BULLETIN INSTRUCTS COLLINS TO INSPECT FOR THE MISSING VALVE AND INSTALL, IF NEEDED.SLOW ACTIVATION TIME OF THE AIR OPERATED PARKING BRAKE SYSTEM COULD HAVE SAFETY CONSEQUENCES.THE PURPOSE OF THE SQ IS TO DETERMINE THE EXTENT OF THE PROBLEM EXPERIENCE, CONSEQUENCES, AND IF A SAFETY RECALL IS WARRANTED.