Airworthiness Directives; Boeing Model 757-200, -200PF, -200CB, and -300 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes, that requires inspection for damage of the W2800 wire bundle insulation, wire conductor, the wire bundle clamp bracket, and the BACC10GU( ) clamp, and repair or replacement with new or serviceable parts, if necessary. This amendment also requires installation of spacers between the clamp and the bracket. This action is necessary to prevent contact between the power feeder wires of the auxiliary power unit (APU) and the clamp bracket aft of the STA 1720 bulkhead due to chafing damage of the Adel clamp and "L" shaped bracket, which could result in electrical arcing and fire, or loss of APU electrical power in the airplane. This action is intended to address the identified unsafe condition.