Action
Final rule.
Summary
We are superseding Airworthiness Directive (AD) 2007-11-08 for all The Boeing Company Model 727 airplanes. AD 2007-11-08 required repetitive inspections of the in-tank fuel boost pump wiring, installation of sleeving over the in-tank fuel boost pump wires, repetitive inspections of a certain electrical wire, sleeve, and conduit, and applicable investigative and corrective actions; and repetitive engine fuel suction feed operational tests. This new AD also requires replacement of the wire bundles for the wing and center fuel boost pumps, installation of convoluted liners, and related investigative and corrective actions if necessary. This new AD also requires replacement of the fuel quantity indicating system (FQIS) wires, a low-frequency eddy current inspection for cracking, and repair if necessary. This new AD also requires revising the maintenance program to incorporate changes to the airworthiness limitations section. This AD was prompted by a report of damage found to the sleeve, jacket, and insulation on an electrical wire during a repetitive inspection. We are issuing this AD to prevent chafing of the fuel boost pump electrical wiring and leakage of fuel into the conduit, and to prevent electrical arcing between the wiring and the surrounding conduit, which could result in arc-through of the conduit, and consequent fire or explosion of the fuel tank.