Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-135 and EMB-145 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain EMBRAER Model EMB-135 and EMB-145 series airplanes, that currently requires revising the airplane flight manual and eventual disconnection of the precooler differential pressure switches. This amendment expands the applicability of the existing AD. This amendment also requires a one-time inspection of those additional airplanes to ensure the disconnection and insulation of the electrical connectors of certain precooler differential pressure switches located in the left and right pylons; and disconnection and insulation of the connectors, if necessary. The actions specified by this AD are intended to prevent incorrect operation of the precooler differential pressure switches, which could result in inappropriate automatic shutoff of the engine bleed valve, and consequent inability to restart a failed engine using cross-bleed from the other engine or possible failure of the anti-ice system. This action is also necessary to ensure that the flightcrew is advised of the procedures necessary to restart an engine in flight using the auxiliary power unit. This action is intended to address the identified unsafe condition.