Summary
This document proposes the supersedure of 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 action would expand the applicability of the existing AD. This action also would require 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. This action is necessary to prevent incorrect operation of the [[Page 41974]] 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.