COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/151 Wing Front Spar Web 8/95 Applicability: All B747-100 aircraft except SP versions. Requirement: Visually and ultrasonically inspect the wing front spar web, upper and lower chords, stiffeners, rib posts and fasteners between front spar stations 570 and 684 in accordance with Boeing Service Bulletin (SB) 747-57A2266, Revision 4. Note: FAA AD 95-02-15 refers. Compliance: Initially inspect before 13 000 flights. Re-inspect at intervals not to exceed 2000 flights. Replacement of fasteners in accordance with Boeing SB 747-57A2266, Revision 4 cancels the requirement of this Directive. Background: An operator has reported a 460 mm crack in the web of the right hand wing front spar. The cracks, occurring above the number two and three engines, will eventually cause a fuel leak which could result in a fire.