Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200 and -300ER series airplanes. This AD requires replacing the low-pressure oxygen flex hoses with new non- conductive low-pressure oxygen flex hoses in the gaseous passenger oxygen system in airplanes equipped with therapeutic oxygen. This AD was prompted by a determination that the low-pressure oxygen flex hoses in the gaseous passenger oxygen system can potentially be conductive. We are issuing this AD to prevent electrical current from passing through the low-pressure oxygen flex hoses in the gaseous passenger oxygen system, which can cause the flex hoses to melt or burn, and a consequent oxygen-fed fire in the passenger cabin.