Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-700, -700C, -800, and -900ER series airplanes, Model 747-400F series airplanes, and Model 767-200 and -300 series airplanes. This AD was prompted by reports indicating that certain crew oxygen mask stowage box units were possibly delivered with a burr in the inlet fitting. The burr might break loose during test or operation, and might pose an ignition source or cause an inlet valve to jam. This final rule adds a step to identify and label certain crew oxygen mask stowage box units that have already been inspected and reworked by the supplier, and allows operators to install new or serviceable crew oxygen mask stowage box units, and requires a general visual inspection for affected serial numbers of the crew oxygen mask stowage box units, and replacement or re-identification as necessary. We are issuing this AD to prevent an ignition source, which could result in an oxygen-fed fire; or an inlet valve jam in a crew oxygen mask stowage box unit, which could result in restricted flow of oxygen.