Summary
This action withdraws a notice of proposed rulemaking (NPRM) that proposed a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes. That action would have required a revision to the FAA-approved Airplane Flight Manual (AFM) to prohibit in-flight operation of the auxiliary power unit (APU). That proposal also would have required inspection of the APU fire extinguisher discharge cartridge for corrosion, and replacement of the discharge cartridge with a new cartridge, if necessary; and modification of the fire extinguishing system tube assembly. Accomplishment of these actions would have terminated the AFM revision. Since the issuance of the NPRM, the manufacturer has advised the Federal Aviation Administration (FAA) that, on all of the affected Model 328-100 series airplanes, the APU fire extinguisher discharge cartridges have been inspected, all corroded discharge cartridges have been replaced with new cartridges, and modification of the fire extinguishing system tube assemblies has been accomplished. Accordingly, the proposed rule is withdrawn.