Federal Aviation Administration November 14, 2016 – Federal Register Recent Federal Regulation Documents

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200, -200LR, -300, and -300ER series airplanes. This AD was prompted by a report indicating that the manufacturer discovered locations where the control components and wiring of the left and right engine fuel spar valves do not have adequate physical separation to meet the redundant system separation requirements. This AD requires modifying the wiring, and installing a new relay bracket and new location for the relay on the left and right engine fuel spar valves. This AD also requires an inspection to identify the part number of the motor operated valve (MOV) actuators for the left and right engine fuel spar valves; replacement of specified MOV actuators with new MOV actuators; certain bonding resistance measurements; and applicable corrective actions. We are issuing this AD to prevent loss of control of both the left and right engine fuel spar valves during a single event, such as local wire bundle damage or a wire bundle fire, which could cause both engines to shut down or result in the inability to control an engine fire.

We are revising an earlier proposal to supersede Airworthiness Directive (AD) 2008-13-12 R1, for certain The Boeing Company Model 737- 100, -200, -200C, -300, -400, and -500 series airplanes. AD 2008-13-12 R1 requires various repetitive inspections for cracking of the upper- frame-to-side-frame splice of the fuselage, and other specified and corrective actions if necessary; and also provides for an optional preventive modification, which would terminate the repetitive inspections. This action revises the notice of proposed rulemaking (NPRM) by adding post-repair/post-modification inspections. We are proposing this SNPRM to detect and correct fatigue cracking of the upper-frame-to-side-frame splice of the fuselage, which could result in reduced structural integrity of the frame and adjacent lap joint, causing increased loading in the fuselage skin, which will accelerate skin crack growth and result in decompression of the airplane. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.