Airworthiness Directives; Boeing Model 767-400ER Series Airplanes and Model 777-200 and -300 Series Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 767-400ER series airplanes and Model 777-200 and - 300 series airplanes. This AD requires, for certain airplanes, repetitive testing of the fill and safety fittings of the cargo fire extinguishing bottles in the forward cargo compartment for leaks; and repetitive application of a corrosion inhibiting compound (CIC) or replacement of the cargo fire extinguishing bottles with reworked fire extinguishing bottles, as necessary. For all airplanes, this AD requires replacement of the cargo fire extinguishing bottles with reworked fire extinguishing bottles, which ends the repetitive tests and CIC applications if applicable. This AD results from failure of the safety fittings for the cargo fire extinguishing bottles. We are issuing this AD to prevent failure of the safety fittings for the cargo fire extinguishing bottles due to corrosion, which could result in leakage of extinguishing agent. If a fire occurs in the cargo bay, the cargo fire extinguishing bottles could have less than enough extinguishing agent to control a fire.