COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/72 Fuselage Crown Crease Beam 10/89 Applicability: Line numbers 66 through 603 except models 747 SP, 747-200 SUD and 747-300 SUD. Requirement: Perform periodic detailed visual and dye penetrant inspections of the body crown crease beam for cracks, in accordance with Boeing Service Bulletin 747-53-2297 Revision 1, dated 26 January 1989. FAA AD 89-08-03 also refers. Compliance: In accordance with FAA AD 89-08-03, except that pressurised flight cycles may be taken in lieu of landings. Background: Five operators have reported cracks in the subject area, which has been determined to be critical to the aircrafts structural integrity. Hence an inspection program which will continue throughout the life of the affected aircraft is prescribed.