AD 2022-04-09 Prompted By Reports Of Cylinder And Valve Assemblies Having Oxygen Leakage

The FAA is adopting a new airworthiness directive (AD) for 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.

This AD was prompted by reports of cylinder and valve assemblies having oxygen leakage from the valve assembly vent hole, caused by the absence of a guide that maintains appropriate spacing between certain parts. This AD requires 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 AD requires 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. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective April 4, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply 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. The NPRM published in the Federal Register on May 1, 2020 (85 FR 25353). The NPRM was prompted by reports of cylinder and valve assemblies having oxygen leakage from the valve assembly vent hole, caused by the absence of a guide that maintains appropriate spacing between certain parts. In the NPRM, the FAA proposed to 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, the NPRM proposed to 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 (removing affected assemblies and installing serviceable assemblies). The NPRM also proposed to require reporting and returning of affected parts to the manufacturer. The FAA is issuing this AD to address oxygen leakage from the cylinder, which could result in decreased or insufficient oxygen supply during a depressurization event; and heating or flow friction, which could cause an ignition event in the valve assembly.

FMI: www.regulations.gov