COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DHC-6 (Twin Otter) Series Aeroplanes AD/DHC-6/8 Amdt 1 Airspeed Placard Installation and Left Elevator Trim Tab - Inspection 1/68 Applicability: All models not incorporating De Havilland of Canada Mod. Bulletins 6/1120, 6/1135 and 6/1142. Requirement: 1. Install the following placard in fuell view of the pilot: "SPEED SHALL NOT EXCEED 125 KTS, I.A.S." 2. On the left elevator trim tab assembly remove the bolt between the push rod and the elevator tab operating lever; operate the tab cockpit control until the screw jack in the elevator is fully retracted and adjust the push rod in order that the bolt can be re-inserted in the lowered tab without exerting pressure on the tab. 3. Ascertain that the total free play measured adjacent to the operating lever with the trim tab in the neutral position does not exceed 0.1 inch at the trailing edge of the tab. 4. Visually inspect the elevator trim tab top and bottom skins for diagonal buckling or concavity other than manufactured flutes. Compliance: For paragraphs 1, 2 and 3 - Forthwith. For paragraph 4 - Before each flight.