Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, that currently requires installation of protective tape on the fire and overheat control unit located in the flight compartment. This action would continue to require the installation of protective tape and would add repetitive inspections of the condition of the protective tape and related corrective action. This action also would mandate eventual replacement of the existing fire and overheat control unit with a modified unit, which would end the repetitive inspections. Additionally, this action would add airplanes to the applicability in the existing AD. The actions specified by the proposed AD are intended to prevent fluid contamination inside the fire and overheat control unit, which could result in a false fire alarm and consequent emergency landing. This action is intended to address the identified unsafe condition.