COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 1900 Series Aeroplanes AD/BEECH 1900/15 Engine Fuel Filter Bypass Valve 2/97 Applicability: Beech 1900C aircraft serial numbers UC-1 through UC-174 and Beech 1900D aircraft serial numbers UE-1 through UE-205. Requirement: To prevent contamination of the engine fuel filter bypass valve resulting in a possible engine shutdown, inspect the engine fuel filter bypass valve in accordance with the requirements of Raytheon Aircraft Mandatory Service Bulletin Number 2678. Note: FAA Airworthiness Directive 96-22-12 refers. Compliance: Effective 30 January 1997: Unless previously accomplished; within 50 hours time in service. Background: This directive has been issued to require certain engine fuel filter bypass valves to be inspected for evidence of contamination. The requirement follows reports of fuel filter bypass valves being contaminated by thread lock adhesive residue. Contamination of the filter bypass valve will not be apparent in service until the filter element becomes clogged, for whatever reason, and failure of the filter bypass valve to open results in a fuel flow interruption and loss of engine power. Federal Register of Legislative Instruments F2006B03633