Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A series airplanes, that would have required replacement of certain air recirculation fans in the flight compartment and the passenger compartment. These fans may be replaced with either upgraded fans with new brushes having insulation on the brush leads or with modified fans having new, brushless motors. That proposal was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. This new action revises the proposed rule by requiring modification of the fan support structure prior to installation of the upgraded fans. The actions specified by this new proposed AD are intended to prevent incidents of smoke or a burning smell in the cabin during flight, caused by incorrect brush insulation in the motors of the air recirculation fans in the flight compartment and the passenger compartment.