COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 188 (Agwagon) Series Aeroplanes AD/CESSNA 188/22 Wing Front and Rear Spar 5/74 Applicability: All models prior to 1972 Agwagon model S/Nos. 188-0001 to 188-00832. Requirement: 1. Inspect for cracks in: (a) the front spar at the splice area near the strut pick-up; (b) the front spar at the fuselage attachment area; (c) the rear spar at the fuselage attachment area; in accordance with Cessna Service Bulletin No. SE 74-4. 2. Inspect for cracks in the upper flange of the rear spar channel at the outer end of the attachment fitting. The inspections shall be carried out using a magnifying glass of at least 4X magnification or alternatively a device such as a "Syte Ade" may be employed. Compliance: 1. For unmodified aircraft - at intervals not exceeding 100 hours time in service. 2. For aircraft modified to Rex Drawing No. RA491, Issue 4 - At intervals not exceeding 150 hours time in service. 3. For aircraft with doubler P/N 1620058.1 installed or service kit called out in SL No. SE 74-4 - at intervals not exceeding 500 hours time in service, after 31 May 1974.