COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 737 Series Aeroplanes AD/B737/43 Amdt 1 Nacelle Strut Firewall Seal 7/92 Applicability: Model 737-300 series with line numbers 1001 through 1485. Requirement: 1. For aircraft listed in Boeing Service Bulletin 737-54-1028; inspect in accordance with Boeing SB 737-54-1028. 2. For aircraft listed in Boeing SB 737-54-1028 Revision 1, that are not subject to Requirement 1; inspect in accordance with Boeing SB 737-54-1028 Revision 1. Note: FAA AD 92-07-02 Amdt 39-8198 refers. Compliance: 1. At the next planned engine removal or within 8,000 hours time in service after 6 September 1990 (the effective date of the initial issue of this Directive). 2. At the next planned engine removal or within 8,000 hours time in service after 25 June 1992, whichever occurs first. The compliance of the previous issue of this Directive is as stated in Requirement 1, and is still current for aircraft initially affected. This Amendment is effective from 25 June 1992. Background: This Directive was prompted by a manufacturer's production report that firewall sealant may not have been applied to all the mating surfaces of the engines' nacelle strut firewall door assemblies. This condition could compromise the integrity of the firewall seal. Amendment 1 is raised to reflect a revision of the relevant FAA AD, which is prompted by information from the manufacturer which indicates that the firewall sealant apparently was not applied properly during production on additional aircraft.