COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 737 Series Aeroplanes AD/B737/27 Amdt 1 TE Flap Track Support Fitting Attach Bolts 8/91 Applicability: Model 737-300 and -400 series as listed in Boeing ASB 737-57A1202 Revision 1. Requirement: Action in accordance with the Technical Requirements of FAA AD 91-09-17 Amdt 39-6984. Compliance: As specified in the Requirement Document with a revised effective date of 8 August 1991 for Australian registered aircraft. Background: Incorrect material bolts and nuts may have been used to attach the outboard flap inboard track support fitting. Amendment 1 is prompted by information from the manufacturer which indicated that additional aircraft were not inspected for the proper nuts before they left the factory.