AD 2022-13-18 Prompted By A Report That There Is The Potential For Electrical Current To Pass Through Low Pressure (LP) Oxygen Flex-Hoses

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-700, 737-800, 747-400, 747-8, 767-400ER, and 777-200 airplanes.

This AD was prompted by a report that there is the potential for electrical current to pass through low pressure (LP) oxygen flex-hoses in the gaseous passenger oxygen system. This AD requires replacing each conductive oxygen flex-hose installed on LP gaseous passenger oxygen systems with a serviceable non-conductive oxygen flex-hose. This AD also prohibits installation of a conductive oxygen flexhose on LP gaseous passenger oxygen systems. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective September 15, 2022.

Supplementary Information: The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0135, dated June 2, 2021 (EASA AD 2021-0135) (also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for certain The Boeing Company Model 737-700, 737-800, 747-400, 747-8, 767-400ER, and 777-200 airplanes with certain Lufthansa Technik AG supplemental type certificates (STCs), which resulted in the installation of conductive oxygen flex-hoses. You may examine the MCAI in the AD docket on the internet at www.regulations.gov by searching for and locating Docket No. FAA-2022-0462. 

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 737-700, 737-800, 747-400, 747-8, 767-400ER, and 777-200 airplanes. The NPRM published in the Federal Register on April 22, 2022 (87 FR 24073). The NPRM was prompted by a report that there is the potential for electrical current to pass through LP oxygen flex-hoses in the gaseous passenger oxygen system. Exposure to electrical faults, such as unintended short circuits, can result in localized electrical heating of the LP oxygen flex-hoses. The NPRM proposed to require replacing each conductive oxygen flex-hose installed on LP gaseous passenger oxygen systems with a serviceable non-conductive oxygen flex-hose. The FAA is issuing this AD to address the possibility of electrical current passing through the LP oxygen flexhoses in the gaseous passenger oxygen system, which could cause the flex-hoses to melt or burn and result in an oxygen-fed fire in the passenger cabin. See the MCAI for additional background information.

FMI: www.regulations.gov