Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that currently requires inspections to detect improper connections of the wire harness installation to the cartridges of the fire extinguishers in the engine nacelles, correction of any discrepancy, and modification of the wiring. This amendment adds a revised modification of that wiring, which, if accomplished, would terminate the inspections currently required by the existing AD. This amendment is prompted by reports indicating that, due to the removal of a certain clamp during maintenance, these fire extinguisher cartridges still could be connected incorrectly after the modification required by the existing AD has been accomplished. The actions specified by this AD are intended to prevent incorrect wiring of the cartridges, which would result in inability of the fire extinguishers to jointly discharge extinguishing agent into a nacelle in the event of an engine fire.