COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 737 Series Aeroplanes AD/B737/7 Fuselage Frames Adjacent to Forward Airstair 8/85 Applicability: All model 737 aircraft, Line Numbers 1 to 880. Requirement: 1. FAA AD 85-01-06, Amendment 39-4982, up to and including Section F, but excluding Section E. 2. Boeing SB 737-53A1064, Revision 3. Compliance: As detailed in Requirement Document No 1. Background: There have been numerous reports of cracking in the fuselage frames adjacent to the forward airstair doorway cut-out. Cracking of the frames and door cut-out internal doubler could result in a sudden loss of cabin pressure, and possibly blowout of the airstair door.