Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2022-04-09, which applies to certain AVOX System Inc. (formerly Scott Aviation) oxygen cylinder and valve assemblies; and oxygen valve assemblies; installed on but not limited to various transport airplanes. AD 2022-04-09 requires an inspection of the oxygen valve assemblies, and oxygen cylinder and valve assemblies, to determine the serial number; for certain assemblies and parts, a detailed inspection of the gap between the bottom of the packing retainer and top of the valve body on the assemblies; and replacement of assemblies having unacceptable gaps. Since the FAA issued AD 2022-04-09, the agency determined additional assemblies and parts are affected by the unsafe condition. This proposed AD would require an inspection of the oxygen valve assemblies, and oxygen cylinder and valve assemblies, to determine the serial number of the valve, cylinder, and entire assembly. For assemblies and parts with certain serial numbers, this proposed AD would require a detailed inspection for correct spacing of the gap between the bottom of the packing retainer and top of the valve body on the assemblies, and replacement of assemblies having unacceptable gaps. This proposed AD would also limit the installation of affected parts under certain conditions. The FAA is proposing this AD to address the unsafe condition on these products.