COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 177 Series Aeroplanes AD/CESSNA 177/30 Amdt 1 Applicability: All models. Wing Main Spar Carry-Through Section 10/90 Requirement: 1. Gain access to the upper and lower surfaces of the wing carry through forging. 2. Inspect the whole wing carry-through forging for any indications of corrosion. Repairs to the wing carry- through forging shall be in accordance with Schemes approved by the Authority. Compliance: Unless already accomplished in accordance with the initial issue of this Directive: 1. For aircraft over ten years time in service since date of manufacture: forthwith, and b. For aircraft with less than ten years time in service since date of manufacture: before attaining ten years time in service, and c. For all aircraft after initial inspection: i) at periods not exceeding six years time in service, or ii) where the spar carry-through has been subjected to an approved corrosion protection scheme: at periods not exceeding twelve years. Background: There have been reports of corrosion in the wing spar carry-through forging on a number of aircraft. In two cases the corrosion was sufficiently advanced to adversely affect the structural integrity of the wing. Amendment 1 reflects the reported results from the initial issue of this Directive. This has enabled a reduction in the initial compliance time and an extension of the repeat inspection period.