Summary
The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model 757 airplanes. The existing AD currently requires inspecting certain power feeder wire bundles for damage, inspecting the support clamps for these wire bundles to determine whether the clamps are properly installed, and performing corrective actions if necessary. This proposed AD would require additional inspections for certain airplanes. This proposed AD results from a report that a power feeder wire bundle chafed against the number six auxiliary slat track, causing electrical wires in the bundle to arc, which damaged both the auxiliary slat track and power feeder wires. We are proposing this AD to prevent arcing that could be a possible ignition source for leaked flammable fluids, which could result in a fire. Arcing could also result in a loss of power from the generator connected to the power feeder wire bundle, and consequent loss of systems, which could reduce controllability of the airplane.