COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Douglas DC3 Series Aeroplanes AD/DC3/12 Reissue Applicability: All models. Oil Dilution Unit - Modification 1/84 Requirement: 1. Remove the 1/4-in OD pipe between the restrictor at the base of the Pioneer pressure warning switch and the oil dilution solenoid. Also remove the 1/4-in OD pipe between the oil dilution solenoid and the "T" drain on the engine oil system. 2. Replace the four hexagon nipples found on the restrictor, oil dilution valve and "T" drain with 1/8-in (gas) Dural plugs. 3. Render the oil dilution switches on the inboard side of the port electrical panel inoperative. Compliance: Unless already accomplished within 100 hours time in service after 29 February 1984. Background: This Directive is reissued with no changes made to the requirement. In order to reduce the possibility of fire, and in view of the fact that the dilution unit is not used in this country, the oil dilution system is rendered inoperative.