COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Douglas DC4 Series Aeroplanes AD/DC4/37 Spar Web - Inspection NK Applicability: All models. Requirement: 1. Inspect the spar web structure in accordance with the following procedure:- 1.1. Open the quick-opening type inspection doors in the bottom of the outer wing and centre section surfaces forward of the front spar and aft of the centre spar. 1.2. Inspect the spar web structure for loose rivets, cracks, seam defects and other irregularities, particular attention being paid to signs of fuel leakage. 2. Repair cracks in the spar web which occur in the area covered by Douglas SB No. (C54)205, or in any other area of the spar, in accordance with the following Douglas Drawings:- 5354811 "Service Rework - Station 463, Outer Wing, Centre Spar" 3344236 "Repair - Integral Tank Spar Web Cracks"; or ANOs Part 100, Appendix "A" Notice No. 7/25; or FAA AD 47-27-2; or ANO 105.1.16.2.6.6.