COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 727 Series Aeroplanes AD/B727/94 Amdt 1 Forward Cargo Compartment Sidewall Frame 1/93 Applicability: All models B727-100 and -100C series aircraft with line numbers 1 to 478 and 480. Requirement: Visually inspect internally the forward cargo compartment sidewall frames from BS 480 to BS 680 for cracks in accordance with Boeing SB 727-53-0068 Revision 4. Note: FAA AD 90-20-14 refers. Compliance: Inspect before 15600 flights, or within 2000 flights after 7 January 1993, or within 9000 flights since the last internal inspection in accordance with the original issue of this AD, or within 4000 flights since the last external inspection in accordance with the original issue of this AD, whichever occurs last. Re-inspect at intervals not exceeding 9000 flights until modified in accordance with Boeing SB 727-53-0068. Background: Cracking of the forward cargo compartment frames was detected during fatigue testing and a number of operators have experienced cracks in those frames. Amendment 1 eliminates the previous option of the external inspection procedure. This procedure has been reassessed as inadequate to prevent a hazardous depressurisation.