Airworthiness Directives; Raytheon Aircraft Company Models 1900, 1900C, and 1900D Airplanes

This amendment supersedes Airworthiness Directive (AD) 97-04- 02, which currently requires installing new exterior placards with operating instructions for the airstair door, cargo door, and emergency exits, as applicable, on certain Raytheon Aircraft Company (Raytheon) Models 1900, 1900C, and 1900D airplanes. This AD requires either modifying the existing exterior placards with door operating instructions installed in accordance with AD 97-04-02; or installing new exterior placards with operating instructions for the airstair door, cargo door, and emergency exits, as applicable. This AD results from reports of the placards (required by AD 97-04-02) covering the atmospheric vents for the cabin door differential pressure lock. The actions specified by this AD are intended to continue to assure that clear and complete operating instructions are visible for opening the airstair door, cargo door, or emergency exits, and to prevent improper operation of the cabin door differential pressure lock caused by the placards blocking the atmospheric vents.