Airworthiness Directives; Raytheon Aircraft Company Beech Model 1900D Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Raytheon Aircraft Company (Raytheon) Beech Model 1900D airplanes that are equipped with a KLN-90B Global Positioning System (GPS) incorporated in accordance with AlliedSignal Supplemental Type Certificate (STC) SA00245WI-D. This AD requires rewiring the KLN- 90B GPS to eliminate the possibility of inconsistent NAV "FLAG" displays. This AD is the result of an instance where the copilot's NAV "FLAG" display was based on the pilot's NAV source validity. The actions specified by this AD are intended to assure that the copilot's NAV "FLAG" displays are based on the copilot's selected NAV source. Inconsistent NAV "FLAG" displays could cause the copilot to make decisions based on an invalid GPS source without knowing it was invalid.