COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/92 Horizontal Stabiliser 6/91 Applicability: Model 747 series with line numbers 002 through 226. Requirement: Action in accordance with the technical requirements of FAA AD 91-05-17 Amdt 39- 6917. Note: Boeing Alert SB 747-53A 2332 refers. Compliance: As specified in the Requirement Document with a revised effective date of 13 June 1991 for Australian registered aircraft. Background: The FAA has received reports of additional cracking detected by the inspections required by a current Airworthiness Directive. This condition, if not corrected, could result in loss of the horizontal stabilizer. Effective date required by the FAA is extended by two months.