Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2005-18- 18, which applies to certain The Boeing Company Model 757 airplanes. AD 2005-18-18 currently requires inspections of certain wire bundles in the left and right engine-to-wing aft fairings for discrepancies; installation of back-to-back p-clamps between the wire and hydraulic supply tube at the aft end of the right-hand strut only; and associated re-routing of the wire bundles, if necessary. Since we issued AD 2005- 18-18, we have determined that the service information referenced in AD 2005-18-18 did not adequately address fuel shutoff valve (FSV) wires at the aft end of the struts. This proposed AD would add an installation of spiral cable wrap on FSV wires at the aft end of the strut, for both left and right engines, and related investigative and corrective actions. We are proposing this AD to prevent chafing between the wire bundle and the structure of the aft fairing, which could result in electrical arcing and subsequent ignition of flammable vapors and possible uncontrollable fire.