The FAA has issued final special conditionsand a request for comments for a supplemental type certificate on the Pilatus PC-12/45 turboprop. The FAA claims this airplane will have novel and unusual design features, including the installation of two Honeywell Model AM-250 electronic barometric altimeters. The agency claims these units do not contain adequate or appropriate airworthiness standards for the protection of these systems from the effects of high intensity radiated fields (HIRF). The published special conditions -- Oct. 31, 2003 -- contain the additional safety standards that the FAA considers necessary to establish a level of safety equivalent to the airworthiness standards applicable to these airplanes. All comments must be received on or before Dec. 15, 2003.