AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. Boeing 737 Series Aeroplanes AD/B737/156 Fuel Tank Vent System 8/2001 Applicability: All Boeing 737-100, -200, -300, -400 and -500 series aircraft. Requirement: Incorporate a flame arrestor and pressure relief valve in the fuel tank vent system in accordance with either: (a) Boeing Service Bulletin 737-28-1131, Revision 2 and Boeing Information Notice 737-28-1131 IN 01, or (b) Shaw Aero Devices, Inc. STC No. SA00859SE, dated December 14, 2000. Note 1: FAA AD 99-03-04, Paragraph (b) refers. Note 2: AD/B737/158 addresses the fuel system wiring provision of FAA AD 99-03- 04, Paragraph (a). Note 3: FAA letter, Reference No. 140S-00-569, approves Shaw Aero Devices, Inc. STC No. SA00859SE, dated December 14, 2000, as an alternative means of compliance for FAA AD 99-03-04. Note 4: Aircraft modified in accordance with previous issues of Boeing SB 737-28- 1131 satisfy the intent of this Airworthiness Directive. Compliance: No later than 10 March 2003. This Airworthiness Directive becomes effective on 9 August 2001. Boeing 737 Series Aeroplanes AD/B737/156 (Continued) Background: This Airworthiness Directive is prompted by testing results obtained during an accident investigation and by re-examination of possible causes of a similar accident. The action introduced by this Airworthiness Directive is intended to reduce the probability of external ignition of fuel vapour exiting the fuel tank vent system and the consequent propagation of the flame front into the fuel tanks. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 2 July 2001 The above AD is notified in the Commonwealth of Australia Gazette on 11 July 2001.