Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain EMBRAER Model EMB-135 and -145 series airplanes. That AD currently requires a one-time inspection to detect incorrect wiring of the electrical connectors to the pressure switches and cartridges on the fire extinguisher bottles for the engines and the auxiliary power unit (APU); disconnection and reconnection of the wiring, as necessary; and adjustment of the length of the harnesses on the fire extinguisher bottles to avoid future misconnections. This action would require additional adjustment of the length of the harnesses; installation of a color-coded identification system to avoid misconnections during maintenance; and a functional test of the engine fire extinguisher system. This action would also expand the applicability of the existing AD to include additional airplanes. The actions specified by the proposed AD are intended to prevent the issuance of erroneous commands or the receipt of erroneous information pertaining to the fire extinguisher system for the engines and the APU, which could result in the inability to put out a fire in an engine or in the APU. This action is intended to address the identified unsafe condition.