COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes AD/TB20/13 Amdt 1 Applicability: Model TB20 and TB21. Fuel Tanks 5/90 Requirement: 1. Unless modified in accordance with Requirement 2, carry out the following action: (a) Position the aircraft in a wings level and a nose-down ground attitude of about 2 degrees. Note: This is achieved on level ground when the height from the ground to the spinner centre equals the height from the ground to the lower part of the rear mooring fitting. (b) Leave the aircraft in this attitude for at least 20 minutes, then drain as described in (c) below; drain from each point at least 500 ml of fuel. (c) Aircraft S/N 1 to 730: Drain L.H wing fuel tank then R.H wing fuel tank. Note: On TB20 and TB21 airplanes, the fuel filter which is located under engine cowling should not be drained as it is not the low point of fuel system. Should filter be drained, apply procedure given in Maintenance Manual concerning filter installation and removal. Aircraft from S/N 731: (i) Select L.H fuel tank (ii) Drain L.H wing fuel tank (iii) Drain fuel filter under fuselage (iv) Drain R.H wing fuel tank. (d) Visually inspect fuel filter caps seals (broken, cracked, torn, kinked) and replace if necessary. Install caps and check security. 2. Modify the fuel tanks in accordance with Socata TB Service Bulletin No. 48. Note: DGAC AD 89-177(A) and Socata TB Service Bulletin No 48 refer. Compliance: 1. For aircraft which have not been flown for one week or more; prior to the next flight after 22 February 1990, and thereafter prior to the next flight any time a period of one week or more occurs between flights. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES For aircraft which are flying at periods of less than one week between flights; within 25 hours time in service after 22 February 1990, and thereafter at periods not exceeding 50 hours time in service. 2. Prior to 28 February 1991. Note: This Directive shall be entered on the Maintenance Release as maintenance required. The inspection required by Para 1 may be performed by the pilot in command, in which case certification is required. A copy of this Directive shall be carried in the aircraft. Background: This Airworthiness Directive is issued to reflect a Country of origin AD which requires regular inspections to detect any water/contamination in the fuel tanks until a modification is incorporated. This relocates the tank drain and outlet holes and reworks rib sections to ensure all drainable water/contamination collects at the tank drain point when the aircraft is in normal ground attitude. Amendment 1 is raised to introduce revisions to the manufacturers document, which clarifies aircraft nose down attitude, and the country of origin AD which increases the period between inspections.