COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 737 Series Aeroplanes AD/B737/92 Thrust Reverser Fan Cowl Firewall 10/95 Applicability: Boeing 737-300, -400, and -500 series aircraft with line numbers 2137 through 2271 inclusive. Requirement: 1. Inspect the inner wall of the thrust reverser fan duct cowl in accordance with Boeing Alert Service Bulletin 737-78A1056 to determine if the correct firewall insulation topcoat material is present and rectify as required. Note: FAA AD 95-09-01 also refers. Compliance: 1. Unless previously accomplished, at next "C" check but no later than 31 December 1996. Background: Boeing has advised that a change to the fireproof insulation on the thrust reverser fan duct firewall to decrease aircraft weight has resulted in the firewall not meeting certification requirements.